.net源码生成器使用SyntaxTree生成代码及简化语法

一、SyntaxTree是什么

SyntaxTree是语法树,是源代码的树形结构表示

由Roslyn编译器生成

在SourceGenerator中会自动生成

整个源代码结构是1个SyntaxTree

SyntaxTree有一个根节点(SyntaxNode)

每个SyntaxNode也包含一个SyntaxTree

这样看整个源代码结构就是片"森林"

csharp 复制代码

public abstract partial class SyntaxNode
{
    // ...
    public SyntaxTree SyntaxTree => this.SyntaxTreeCore;
}

public abstract class SyntaxTree
{
    // ...
    public SyntaxNode GetRoot(CancellationToken cancellationToken = default)
    {
        return GetRootCore(cancellationToken);
    }
}

二、SyntaxTree的作用

1. 分析源代码

用于分析本次增量代码

是否满足生成器规则

找出指定的类、方法及特性(Attribute)

2. 直接用来生成代码

源代码字符串可以转化为SyntaxTree

SyntaxTree也可以转化为源代码

也可以部分用字符串转化为SyntaxTree组合使用

3. SyntaxTree生成代码有优势

直接生成语法树保证语法的正确性和准确性

原生csharp代码,更方便开发和调试

SyntaxTree不会生成过多的字符串碎片

4. SyntaxTree生成代码的方法

一般使用SyntaxFactory类来生成代码

笔者对部分功能进行简化,使得生成代码更简单

dotnet add package Hand.Generators.EasySyntax --version 0.1.0.1-alpha

希望通过本篇文章引导大家把拼接字符串生成代码的方式替换为使用SyntaxTree

三、SyntaxTree基本元素

1. 声明命名空间

1.1 默认方式

csharp 复制代码

var ns = SyntaxFactory.NamespaceDeclaration(SyntaxFactory.IdentifierName("Models"));
var fns = SyntaxFactory.FileScopedNamespaceDeclaration(SyntaxFactory.IdentifierName("Services"));

1.2 简化方式

csharp 复制代码

var ns = SyntaxGenerator.NamespaceDeclaration("Models");
var fns = SyntaxGenerator.FileScopedNamespaceDeclaration("Services");

1.3 生成的代码

csharp 复制代码

namespace Models
{
}

namespace Services;

2. 预定义类型

2.1 默认方式

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.BoolKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.ByteKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.SByteKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.UIntKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.ShortKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.UShortKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.LongKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.ULongKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.FloatKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.DoubleKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.DecimalKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.CharKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.ObjectKeyword))

SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.VoidKeyword))

2.2 简化方式

SyntaxGenerator.BoolType

SyntaxGenerator.ByteType

SyntaxGenerator.SByteType

SyntaxGenerator.IntType

SyntaxGenerator.UIntType

SyntaxGenerator.ShortType

SyntaxGenerator.UShortType

SyntaxGenerator.LongType

SyntaxGenerator.ULongType

SyntaxGenerator.FloatType

SyntaxGenerator.DoubleType

SyntaxGenerator.DecimalType

SyntaxGenerator.StringType

SyntaxGenerator.CharType

SyntaxGenerator.ObjectType

SyntaxGenerator.VoidType

2.3 生成的代码

bool

byte

sbyte

int

uint

short

ushort

long

ulong

float

double

decimal

string

char

object

void

3. 常量表达式

3.1 默认方式

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1))

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1U))

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1L))

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1UL))

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1F))

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1D))

SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1M))

SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("abc"))

SyntaxFactory.LiteralExpression(SyntaxKind.CharacterLiteralExpression, SyntaxFactory.Literal('a'))

SyntaxFactory.LiteralExpression(SyntaxKind.TrueLiteralExpression)

SyntaxFactory.LiteralExpression(SyntaxKind.FalseLiteralExpression)

SyntaxFactory.LiteralExpression(SyntaxKind.NullLiteralExpression)

SyntaxFactory.LiteralExpression(SyntaxKind.DefaultLiteralExpression)

SyntaxFactory.ObjectCreationExpression(SyntaxFactory.IdentifierName("Object"))

SyntaxFactory.ImplicitObjectCreationExpression()

SyntaxFactory.CollectionExpression()

3.2 简化方式

SyntaxGenerator.Literal(1)

SyntaxGenerator.Literal(1U)

SyntaxGenerator.Literal(1L)

SyntaxGenerator.Literal(1UL)

SyntaxGenerator.Literal(1F)

SyntaxGenerator.Literal(1D)

SyntaxGenerator.Literal(1M)

SyntaxGenerator.Literal("abc")

SyntaxGenerator.Literal('a')

SyntaxGenerator.TrueLiteral

SyntaxGenerator.FalseLiteral

SyntaxGenerator.NullLiteral

SyntaxGenerator.DefaultLiteral

SyntaxFactory.IdentifierName("Object").New()

3.3 生成的代码

1

1U

1L

1UL

1F

1D

ushort

1M

"abc"

'a'

true

null

default

new Object()

new()

4. 运算

4.1 默认方式

SyntaxFactory.BinaryExpression(SyntaxKind.AddExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.SubtractExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.MultiplyExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.DivideExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.ModuloExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.LeftShiftExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.RightShiftExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.BitwiseAndExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.BitwiseOrExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.ExclusiveOrExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.LogicalAndExpression, left, right)

SyntaxFactory.BinaryExpression(SyntaxKind.LogicalOrExpression, left, right)

SyntaxFactory.PrefixUnaryExpression(SyntaxKind.PreIncrementExpression, variable)

SyntaxFactory.PrefixUnaryExpression(SyntaxKind.PreDecrementExpression, variable)

SyntaxFactory.PostfixUnaryExpression(SyntaxKind.PostIncrementExpression, variable)

SyntaxFactory.PostfixUnaryExpression(SyntaxKind.PostDecrementExpression, variable)

SyntaxFactory.PrefixUnaryExpression(SyntaxKind.BitwiseNotExpression, variable)

SyntaxFactory.PrefixUnaryExpression(SyntaxKind.LogicalNotExpression, variable)

SyntaxFactory.QualifiedName(prefix, name)

SyntaxFactory.MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, owner, member)

SyntaxFactory.ConditionalAccessExpression(owner, SyntaxFactory.MemberBindingExpression(SyntaxFactory.IdentifierName(member)))

4.2 简化方式(扩展方法)

left.Add(right)

left.Subtract(right)

left.Multiply(right)

left.Divide(right)

left.Modulo(right)

left.LeftShift(right)

left.RightShift(right)

left.And(right)

left.Or(right)

left.XOr(right)

left.LogicalAnd(right)

left.LogicalOr(right)

variable.PreIncrement()

variable.PreDecrement()

variable.PostIncrement()

variable.PostDecrement()

variable.Not()

variable.LogicalNot()

name.Qualified(prefix)

owner.Access(member)

owner.ConditionalAccess(member)

4.3 生成的代码

left + right

left - right

left * right

left / right

left % right

left << right

left >> right

left & right

left | right

left ^ right

left && right

left || right

++variable

--variable

variable++

variable--

~variable

!variable

prefix.name

owner.member

owner?.member

5. 定义变量

5.1 默认方式

csharp 复制代码

var x = SyntaxFactory.VariableDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))
    .AddVariables(SyntaxFactory.VariableDeclarator("x"));
var y = SyntaxFactory.VariableDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))
    .AddVariables(SyntaxFactory.VariableDeclarator("y")
        .WithInitializer(SyntaxFactory.EqualsValueClause(
            SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1)))));
var z = SyntaxFactory.VariableDeclaration(SyntaxFactory.IdentifierName(SyntaxFactory.Token(SyntaxKind.VarKeyword)))
    .AddVariables(SyntaxFactory.VariableDeclarator("z")
        .WithInitializer(SyntaxFactory.EqualsValueClause(
            SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1)))));

5.2 简化方式

csharp 复制代码

var x = SyntaxGenerator.IntType.Variable("x");
var y = SyntaxGenerator.IntType.Variable("y", SyntaxGenerator.Literal(1));
var z = SyntaxGenerator.IntType.Variable("z", SyntaxGenerator.Literal(1));

5.3 生成的代码

csharp 复制代码

int x;
int y = 1;
var z = 1;

6. 定义参数

6.1 默认方式

csharp 复制代码

var a = SyntaxFactory.Parameter(SyntaxFactory.Identifier("a"))
    .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)));
var b = SyntaxFactory.Parameter(SyntaxFactory.Identifier("b"))
    .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))
    .WithDefault(SyntaxFactory.EqualsValueClause(
        SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1))));

6.2 简化方式

csharp 复制代码

var a = SyntaxGenerator.IntType.Parameter("a");
var b = SyntaxGenerator.IntType.Parameter("b", SyntaxGenerator.Literal(1));

6.3 生成的代码

csharp 复制代码

int a

csharp 复制代码

int b = 1

7.定义函数

7.1 默认方式

csharp 复制代码

var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)), "Increment")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(SyntaxFactory.Identifier("num"))
            .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))),
        SyntaxFactory.Parameter(SyntaxFactory.Identifier("value"))
            .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))
            .WithDefault(SyntaxFactory.EqualsValueClause(
                SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1))))
    )
    .WithBody(SyntaxFactory.Block(
        SyntaxFactory.ReturnStatement(
            SyntaxFactory.BinaryExpression(SyntaxKind.AddExpression,
                SyntaxFactory.IdentifierName("num"),
                SyntaxFactory.IdentifierName("value"))
        )
    ));

7.2 简化方式

csharp 复制代码

var num = SyntaxFactory.IdentifierName("num");
var value = SyntaxFactory.IdentifierName("value");
var method = SyntaxGenerator.IntType.Method("Increment", 
        SyntaxGenerator.IntType.Parameter(num.Identifier), 
        SyntaxGenerator.IntType.Parameter(value.Identifier, SyntaxGenerator.Literal(1)))
    .ToBuilder()
    .Return(num.Add(value));

7.3 生成的代码

csharp 复制代码

int Increment(int num, int value = 1)
{
    return num + value;
}

8. 定义字段

8.1 默认方式

csharp 复制代码

var _x = SyntaxFactory.FieldDeclaration(SyntaxFactory.VariableDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))))
    .AddDeclarationVariables(
        SyntaxFactory.VariableDeclarator("_x")
    );
var _y = SyntaxFactory.FieldDeclaration(SyntaxFactory.VariableDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))))
    .AddDeclarationVariables(
        SyntaxFactory.VariableDeclarator("_y")
        .WithInitializer(SyntaxFactory.EqualsValueClause(
            SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1)))
        )
    );

8.2 简化方式

csharp 复制代码

var _x = SyntaxGenerator.IntType.Field("_x");
var _y = SyntaxGenerator.IntType.Field("_y", SyntaxGenerator.Literal(1));

8.3 生成的代码

csharp 复制代码

int _x;
int _y = 1;

9. 定义属性

9.1 默认方式

csharp 复制代码

var Id = SyntaxFactory.PropertyDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)), SyntaxFactory.Identifier("Id"))
    .AddAccessorListAccessors(
        SyntaxFactory.AccessorDeclaration(SyntaxKind.GetAccessorDeclaration)
            .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken)),
        SyntaxFactory.AccessorDeclaration(SyntaxKind.SetAccessorDeclaration)
            .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken))
    );
var Name = SyntaxFactory.PropertyDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword)), SyntaxFactory.Identifier("Name"))
    .AddAccessorListAccessors(
        SyntaxFactory.AccessorDeclaration(SyntaxKind.GetAccessorDeclaration)
            .AddBodyStatements(SyntaxFactory.ReturnStatement(SyntaxFactory.IdentifierName("_name")))
    );
var Age = SyntaxFactory.PropertyDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)), SyntaxFactory.Identifier("Age"))
    .AddAccessorListAccessors(
        SyntaxFactory.AccessorDeclaration(SyntaxKind.GetAccessorDeclaration)
            .AddBodyStatements(SyntaxFactory.ReturnStatement(SyntaxFactory.IdentifierName("_age"))),
        SyntaxFactory.AccessorDeclaration(SyntaxKind.SetAccessorDeclaration)
            .AddBodyStatements(SyntaxFactory.ExpressionStatement(
                SyntaxFactory.AssignmentExpression(SyntaxKind.SimpleAssignmentExpression, SyntaxFactory.IdentifierName("_age"), SyntaxFactory.IdentifierName("value"))))
    );

9.2 简化方式

csharp 复制代码

var Id = SyntaxGenerator.IntType.Property(SyntaxFactory.Identifier("Id"), SyntaxKind.GetAccessorDeclaration, SyntaxKind.SetAccessorDeclaration);
var Name = SyntaxGenerator.StringType.GetOnlyProperty(SyntaxFactory.Identifier("Name"), SyntaxFactory.IdentifierName("_name"));
var getAge = SyntaxGenerator.PropertyGetDeclaration().ToBuilder().Return(SyntaxFactory.IdentifierName("_age"));
var setAge = SyntaxGenerator.PropertySetDeclaration().ToBuilder().Add(SyntaxFactory.IdentifierName("_age").AssignValue()).End();
var property = SyntaxGenerator.IntType.Property(SyntaxFactory.Identifier("Age"), getAge, setAge);

9.3 生成的代码

csharp 复制代码

int Id { get; set; }
string Name
{
    get
    {
        return _name;
    }
}
int Age
{
    get
    {
        return _age;
    }

    set
    {
        _age = value;
    }
}

10. 声明类和结构体

10.1 默认方式

csharp 复制代码

var userClass = SyntaxFactory.ClassDeclaration("UserClass");
var userStruct = SyntaxFactory.StructDeclaration("UserStruct");

10.2. 无简化方式

10.3. 生成的代码

csharp 复制代码

class UserClass
{
}
struct UserStruct
{
}

11.定义构造函数

11.1 默认方式

csharp 复制代码

var constructor = SyntaxFactory.ConstructorDeclaration("UserId")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(SyntaxFactory.Identifier("original"))
            .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))))
    .AddBodyStatements(SyntaxFactory.ExpressionStatement(
        SyntaxFactory.AssignmentExpression(SyntaxKind.SimpleAssignmentExpression, SyntaxFactory.IdentifierName("_original"), SyntaxFactory.IdentifierName("original"))));

11.2 简化方式

csharp 复制代码

var type = SyntaxFactory.ClassDeclaration("UserId");
var original = SyntaxFactory.IdentifierName("original");
var constructor = type.Constructor(SyntaxGenerator.IntType.Parameter(original.Identifier))
    .ToBuilder()
    .Add(SyntaxFactory.IdentifierName("_original").Assign(original))
    .End();

11.3. 生成的代码

csharp 复制代码

UserId(int original)
{
    _original = original;
}

12. 声明记录类

12.1 默认方式

csharp 复制代码

var record = SyntaxFactory.RecordDeclaration(SyntaxFactory.Token(SyntaxKind.RecordKeyword), "Person")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(SyntaxFactory.Identifier("Name"))
            .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword)))
    )
    .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken));

12.2 简化方式

csharp 复制代码

var record = SyntaxGenerator.RecordDeclaration("Person")
    .AddParameterListParameters(
        SyntaxGenerator.StringType.Parameter("Name")
    )
    .WithSemicolonToken();

12.3 生成的代码

csharp 复制代码

record Person(string Name);

13. 声明记录结构体

13.1 默认方式

csharp 复制代码

var recordDeclaration = SyntaxFactory.RecordDeclaration(SyntaxKind.RecordStructDeclaration, SyntaxFactory.Token(SyntaxKind.RecordKeyword), SyntaxFactory.Identifier("UserId"))
    .WithClassOrStructKeyword(SyntaxFactory.Token(SyntaxKind.StructKeyword))
    .AddParameterListParameters(
        SyntaxFactory.Parameter(SyntaxFactory.Identifier("Id"))
            .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))
    )            
    .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken));

13.2 简化方式

csharp 复制代码

var type = SyntaxGenerator.RecordStructDeclaration("UserId")
    .AddParameterListParameters(
        SyntaxGenerator.IntType.Parameter("Id")
    )
    .WithSemicolonToken();

13.3 生成的代码

csharp 复制代码

record struct UserId(int Id);

14. 访问修饰符

14.1 访问修饰符种类

private

protected

internal

public

14.2 默认方式

csharp 复制代码

var field = SyntaxFactory.FieldDeclaration(
    SyntaxFactory.VariableDeclaration(
        SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)),
        SyntaxFactory.SingletonSeparatedList(
            SyntaxFactory.VariableDeclarator(SyntaxFactory.Identifier("_id"))
        )
    ))
    .AddModifiers(SyntaxFactory.Token(SyntaxKind.PrivateKeyword));
var property = SyntaxFactory.PropertyDeclaration(
    SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)),
    SyntaxFactory.Identifier("Id"))
    .AddModifiers(SyntaxFactory.Token(SyntaxKind.PublicKeyword))
    .AddAccessorListAccessors(
        SyntaxFactory.AccessorDeclaration(SyntaxKind.GetAccessorDeclaration)
            .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken)),
        SyntaxFactory.AccessorDeclaration(SyntaxKind.InitAccessorDeclaration)
            .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken))
    );

14.3 简化方式

csharp 复制代码

var field = SyntaxGenerator.IntType.Field("_id")
    .Private();
var property = SyntaxGenerator.IntType.Property("Id", 
        SyntaxKind.GetAccessorDeclaration, 
        SyntaxKind.InitAccessorDeclaration)
    .Public();

14.4 生成的代码

csharp 复制代码

private int _id;
public int Id { get; init; }

15. 字段修饰符

13.1 字段修饰符种类

readonly

const

volatile‌

15.2 默认方式

csharp 复制代码

var field = SyntaxFactory.FieldDeclaration(
    SyntaxFactory.VariableDeclaration(
        SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)),
        SyntaxFactory.SingletonSeparatedList(
            SyntaxFactory.VariableDeclarator(SyntaxFactory.Identifier("_id"))
        )
    ))
    .AddModifiers(
        SyntaxFactory.Token(SyntaxKind.PrivateKeyword), 
        SyntaxFactory.Token(SyntaxKind.ReadOnlyKeyword));

15.3 简化方式

csharp 复制代码

var field = SyntaxGenerator.IntType.Field("_id")
     .Private()
     .ReadOnly();

15.4 生成的代码

csharp 复制代码

private readonly int _id;

16. 参数修饰符

16.1 参数修饰符种类

params

in

ref

out

16.2 默认方式

csharp 复制代码

var parameter = SyntaxFactory.Parameter(SyntaxFactory.Identifier("name"))
    .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword)))
    .AddModifiers(SyntaxFactory.Token(SyntaxKind.RefKeyword));

16.3 简化方式

csharp 复制代码

var parameter = SyntaxGenerator.StringType.Parameter("name")
    .Ref();

16.4 生成的代码

csharp 复制代码

ref string name

17. 方法修饰符

17.1 方法修饰符种类

virtual‌

override

extern‌

async

17.2 默认方式

csharp 复制代码

var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword)), "CreateId")
    .AddModifiers(SyntaxFactory.Token(SyntaxKind.VirtualKeyword))
    .WithBody(
        SyntaxFactory.Block(SyntaxFactory.ReturnStatement(
            SyntaxFactory.PostfixUnaryExpression(SyntaxKind.PostIncrementExpression, SyntaxFactory.IdentifierName("_seed"))))
    );

17.3 简化方式

csharp 复制代码

var method = SyntaxGenerator.IntType.Method("CreateId")
    .Virtual()
    .ToBuilder()
    .Return(SyntaxFactory.IdentifierName("_seed").PostIncrement());

17.4 生成的代码

csharp 复制代码

virtual int CreateId()
{
    return _seed++;
}

18. 其他修饰符

18.1 其他修饰符种类

abstract

sealed

new

static‌

partial

18.2 默认方式

csharp 复制代码

var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword)), "CreateId")
    .AddModifiers(SyntaxFactory.Token(SyntaxKind.PartialKeyword))
    .WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken));

18.3 简化方式

csharp 复制代码

var method = SyntaxGenerator.IntType.Method("CreateId")
    .Partial()
    .WithSemicolonToken();

18.4 生成的代码

csharp 复制代码

partial int CreateId();

四、方法体定义

1. 方法体构造器

调用ToBuilder简化方法体定义

1.1 支持构造函数、方法和属性

csharp 复制代码

var type = SyntaxFactory.ClassDeclaration("UserId");
var original = SyntaxFactory.IdentifierName("original");
var constructor = type.Constructor(SyntaxGenerator.IntType.Parameter(original.Identifier))
    .ToBuilder()
    .Add(SyntaxFactory.IdentifierName("_original").Assign(original))
    .End();

var num = SyntaxFactory.IdentifierName("num");
var value = SyntaxFactory.IdentifierName("value");
var method = SyntaxGenerator.IntType.Method("Increment", 
        SyntaxGenerator.IntType.Parameter(num.Identifier), 
        SyntaxGenerator.IntType.Parameter(value.Identifier, SyntaxGenerator.Literal(1)))
    .ToBuilder()
    .Return(num.Add(value));

var getAge = SyntaxGenerator.PropertyGetDeclaration()
    .ToBuilder()
    .Return(SyntaxFactory.IdentifierName("_age"));
var setAge = SyntaxGenerator.PropertySetDeclaration()
    .ToBuilder()
    .Add(SyntaxFactory.IdentifierName("_age").AssignValue())
    .End();
var property = SyntaxGenerator.IntType.Property(SyntaxFactory.Identifier("Age"), getAge, setAge);

1.2 生成的代码

csharp 复制代码

UserId(int original)
{
    _original = original;
}

int Increment(int num, int value = 1)
{
    return num + value;
}


int Age
{
    get
    {
        return _age;
    }

    set
    {
        _age = value;
    }
}

2. if/else分支逻辑

2.1 默认方式

csharp 复制代码

var value = SyntaxFactory.IdentifierName("value");
var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword)), "BoolToString")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(value.Identifier)
            .WithType(SyntaxFactory.NullableType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.BoolKeyword)))))
    .AddBodyStatements(
        SyntaxFactory.IfStatement(
            SyntaxFactory.BinaryExpression(SyntaxKind.EqualsExpression, value, SyntaxFactory.LiteralExpression(SyntaxKind.NullLiteralExpression)),
            SyntaxFactory.ReturnStatement(SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("false"))),
            SyntaxFactory.ElseClause(
                SyntaxFactory.IfStatement(
                value,
                SyntaxFactory.ReturnStatement(SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("true"))),
                SyntaxFactory.ElseClause(SyntaxFactory.ReturnStatement(SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("false")))))))
    );

2.2 简化方式

csharp 复制代码

var value = SyntaxFactory.IdentifierName("value");
var method = SyntaxGenerator.StringType.Method("BoolToString", SyntaxGenerator.BoolType.Nullable().Parameter(value.Identifier))
    .ToBuilder()
    .If(value.IsNull())
        .Add(SyntaxGenerator.Literal("false").Return())
    .ElseIf(value)
        .Return(SyntaxGenerator.Literal("true"))
    .Return(SyntaxGenerator.Literal("false"));

2.3 生成的代码

csharp 复制代码

string BoolToString(bool? value)
{
    if (value == null)
        return "false";
    else if (value)
        return "true";
    return "false";
}

3. switch/case分支逻辑

3.1 默认方式

csharp 复制代码

var value = SyntaxFactory.IdentifierName("value");
var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.BoolKeyword)), "IntToBool")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(value.Identifier)
            .WithType(SyntaxFactory.NullableType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))))
    .AddBodyStatements(
        SyntaxFactory.SwitchStatement(value)
            .AddSections(
                SyntaxFactory.SwitchSection(
                    SyntaxFactory.SingletonList<SwitchLabelSyntax>(SyntaxFactory.CaseSwitchLabel(
                        SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(0)))),
                    SyntaxFactory.SingletonList<StatementSyntax>(SyntaxFactory.ReturnStatement(
                        SyntaxFactory.LiteralExpression(SyntaxKind.FalseLiteralExpression)))),
                SyntaxFactory.SwitchSection(
                    SyntaxFactory.SingletonList<SwitchLabelSyntax>(SyntaxFactory.CaseSwitchLabel(
                        SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1)))),
                    SyntaxFactory.SingletonList<StatementSyntax>(SyntaxFactory.ReturnStatement(
                        SyntaxFactory.LiteralExpression(SyntaxKind.TrueLiteralExpression)))),
                SyntaxFactory.SwitchSection(
                    SyntaxFactory.SingletonList<SwitchLabelSyntax>(SyntaxFactory.DefaultSwitchLabel()),
                    SyntaxFactory.SingletonList<StatementSyntax>(SyntaxFactory.ReturnStatement(
                        SyntaxFactory.LiteralExpression(SyntaxKind.TrueLiteralExpression)))))
    );

3.2 简化方式

csharp 复制代码

var value = SyntaxFactory.IdentifierName("value");
var method = SyntaxGenerator.BoolType.Method("IntToBool", SyntaxGenerator.IntType.Parameter(value.Identifier))
    .ToBuilder()
    .Switch(value)
        .Case(SyntaxGenerator.Literal(0))
            .Add(SyntaxGenerator.FalseLiteral.Return())
        .Case(SyntaxGenerator.Literal(1))
            .Add(SyntaxGenerator.TrueLiteral.Return())
        .Default()
            .Return(SyntaxGenerator.TrueLiteral)
    .End();

3.3 生成的代码

csharp 复制代码

bool IntToBool(int value)
{
    switch (value)
    {
        case 0:
            return false;
        case 1:
            return true;
        default:
            return true;
    }
}

4. foreach循环

4.1 默认方式

csharp 复制代码

var list = SyntaxFactory.IdentifierName("list");
var item = SyntaxFactory.IdentifierName("item");
var count = SyntaxFactory.IdentifierName("count");
var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)), "Count")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(list.Identifier)
            .WithType(SyntaxFactory.ArrayType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)))))
    .AddBodyStatements(
        SyntaxFactory.LocalDeclarationStatement(SyntaxFactory.VariableDeclaration(
            SyntaxFactory.IdentifierName("var"), SyntaxFactory.SingletonSeparatedList(
                SyntaxFactory.VariableDeclarator(count.Identifier)
                    .WithInitializer(SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, 
                        SyntaxFactory.Literal(0)))))),
        SyntaxFactory.ForEachStatement(
            SyntaxFactory.IdentifierName("var"), 
            item.Identifier, 
            list, 
            SyntaxFactory.ExpressionStatement(
                SyntaxFactory.AssignmentExpression(SyntaxKind.AddAssignmentExpression, count, item))),
        SyntaxFactory.ReturnStatement(count)
    );

4.2 简化方式

csharp 复制代码

var list = SyntaxFactory.IdentifierName("list");
var item = SyntaxFactory.IdentifierName("item");
var count = SyntaxFactory.IdentifierName("count");
var method = SyntaxGenerator.IntType.Method("Count", SyntaxGenerator.IntType.Array().Parameter(list.Identifier))
    .ToBuilder()
    .Declare(SyntaxGenerator.VarType.Variable(count.Identifier, SyntaxGenerator.Literal(0)))
    .ForEach(SyntaxGenerator.VarType, item.Identifier, list)
        .Add(count.AddAssign(item))
    .End()
    .Return(count);

4.3 生成的代码

csharp 复制代码

int Count(int[] list)
{
    var count = 0;
    foreach (var item in list)
        count += item;
    return count;
}

5. for循环

5.1 默认方式

csharp 复制代码

var i = SyntaxFactory.IdentifierName("i");
var num = SyntaxFactory.IdentifierName("num");
var count = SyntaxFactory.IdentifierName("count");
var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)), "Total")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(num.Identifier)
            .WithType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))))
    .AddBodyStatements(
        SyntaxFactory.LocalDeclarationStatement(SyntaxFactory.VariableDeclaration(
            SyntaxFactory.IdentifierName("var"), SyntaxFactory.SingletonSeparatedList(
                SyntaxFactory.VariableDeclarator(count.Identifier)
                    .WithInitializer(SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression,
                        SyntaxFactory.Literal(0)))))),
        SyntaxFactory.ForStatement(
            SyntaxFactory.VariableDeclaration(
                SyntaxFactory.IdentifierName("var")).AddVariables(
                    SyntaxFactory.VariableDeclarator(i.Identifier)
                        .WithInitializer(SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression,
                            SyntaxFactory.Literal(0)))),
            default,
            SyntaxFactory.BinaryExpression(SyntaxKind.LessThanExpression, i, num),
            SyntaxFactory.SingletonSeparatedList<ExpressionSyntax>(SyntaxFactory.PostfixUnaryExpression(SyntaxKind.PostIncrementExpression, i)),
            SyntaxFactory.ExpressionStatement(SyntaxFactory.AssignmentExpression(SyntaxKind.AddAssignmentExpression, count, i))),
        SyntaxFactory.ReturnStatement(count)
    );

5.2 简化方式

csharp 复制代码

var i = SyntaxFactory.IdentifierName("i");
var num = SyntaxFactory.IdentifierName("num");
var count = SyntaxFactory.IdentifierName("count");
var method = SyntaxGenerator.IntType.Method("Total", SyntaxGenerator.IntType.Parameter(num.Identifier))
    .ToBuilder()
    .Declare(SyntaxGenerator.IntType.Variable(count.Identifier, SyntaxGenerator.Literal(0)))
    .For(i, num)
        .Add(count.AddAssign(i))
    .End()
    .Return(count);

5.3 生成的代码

csharp 复制代码

int Total(int num)
{
    int count = 0;
    for (var i = 0; i < num; i++)
        count += i;
    return count;
}

6. while循环

6.1 默认方式

csharp 复制代码

var readerType = SyntaxFactory.IdentifierName("DbDataReader");
var reader = SyntaxFactory.IdentifierName("reader");
var listType = SyntaxFactory.GenericName("List")
    .AddTypeArgumentListArguments(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword)));
var list = SyntaxFactory.IdentifierName("list");
var getFieldValue = SyntaxFactory.QualifiedName(
    reader, 
    SyntaxFactory.GenericName("GetFieldValue")
        .AddTypeArgumentListArguments(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.IntKeyword))));
var method = SyntaxFactory.MethodDeclaration(listType, "GetIds")
    .AddParameterListParameters(
        SyntaxFactory.Parameter(reader.Identifier)
            .WithType(readerType)
    )
    .AddBodyStatements(
        SyntaxFactory.LocalDeclarationStatement(SyntaxFactory.VariableDeclaration(
            listType, SyntaxFactory.SingletonSeparatedList(
                SyntaxFactory.VariableDeclarator(list.Identifier)
                    .WithInitializer(SyntaxFactory.CollectionExpression())))),
        SyntaxFactory.WhileStatement(
            SyntaxFactory.InvocationExpression(SyntaxFactory.MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, reader, SyntaxFactory.IdentifierName("Read"))),
            SyntaxFactory.ExpressionStatement(
                SyntaxFactory.InvocationExpression(SyntaxFactory.MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, list, SyntaxFactory.IdentifierName("Add")))
                    .AddArgumentListArguments(SyntaxFactory.Argument(
                        SyntaxFactory.InvocationExpression(getFieldValue)
                        .AddArgumentListArguments(SyntaxFactory.Argument(
                            SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(0))
                        ))
                    ))
            )
        ),
        SyntaxFactory.ReturnStatement(list)
    );

6.2 简化方式

csharp 复制代码

 var readerType = SyntaxFactory.IdentifierName("DbDataReader");        
 var reader = SyntaxFactory.IdentifierName("reader");
 var listType = SyntaxGenerator.Generic("List", SyntaxGenerator.IntType);
 var list = SyntaxFactory.IdentifierName("list");
 var getFieldValue = SyntaxGenerator.Generic("GetFieldValue", SyntaxGenerator.IntType).Qualified(reader);
 var method = listType.Method("GetIds", readerType.Parameter(reader.Identifier))
     .ToBuilder()
     .Declare(listType.Variable(list.Identifier, SyntaxFactory.CollectionExpression()))
     .While(reader.Access("Read").Invocation())
         .Add(list.Access("Add").Invocation([getFieldValue.Invocation([SyntaxGenerator.Literal(0)])]))
     .End()
     .Return(list);

6.3 生成的代码

csharp 复制代码

List<int> GetIds(DbDataReader reader)
{
    List<int> list = [];
    while (reader.Read())
        list.Add(reader.GetFieldValue<int>(0));
    return list;
}

6. do/while循环

6.1 默认方式

csharp 复制代码

var console = SyntaxFactory.IdentifierName("Console");
var writeLine = console.Access("WriteLine");
var thing = SyntaxFactory.IdentifierName("thing");
var method = SyntaxFactory.MethodDeclaration(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.VoidKeyword)), "DoSTh")
    .AddBodyStatements(
        SyntaxFactory.LocalDeclarationStatement(SyntaxFactory.VariableDeclaration(
            SyntaxFactory.NullableType(SyntaxFactory.PredefinedType(SyntaxFactory.Token(SyntaxKind.StringKeyword))), SyntaxFactory.SingletonSeparatedList(
                SyntaxFactory.VariableDeclarator(thing.Identifier)))),
        SyntaxFactory.ExpressionStatement(
            SyntaxFactory.InvocationExpression(writeLine)
               .AddArgumentListArguments(SyntaxFactory.Argument(
                   SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("Enter some things:"))
               ))
        ),
        SyntaxFactory.DoStatement(
            SyntaxFactory.Block(
                SyntaxFactory.ExpressionStatement(SyntaxFactory.AssignmentExpression(SyntaxKind.SimpleAssignmentExpression,
                    thing,
                    SyntaxFactory.InvocationExpression(SyntaxFactory.MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, console, SyntaxFactory.IdentifierName("ReadLine"))))),
                SyntaxFactory.ExpressionStatement(
                    SyntaxFactory.InvocationExpression(SyntaxFactory.MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, console, SyntaxFactory.IdentifierName("Write")))
                        .AddArgumentListArguments(SyntaxFactory.Argument(
                            SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("Do "))
                        ))
                ),
                SyntaxFactory.ExpressionStatement(
                    SyntaxFactory.InvocationExpression(writeLine)
                        .AddArgumentListArguments(SyntaxFactory.Argument(thing))
                )
            ),
            thing.NotEqual(SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression, SyntaxFactory.Literal("exit"))))
    );

6.2 简化方式

csharp 复制代码

var console = SyntaxFactory.IdentifierName("Console");
var writeLine = console.Access("WriteLine");
var thing = SyntaxFactory.IdentifierName("thing");
var method = SyntaxGenerator.VoidType.Method("DoSTh")
    .ToBuilder()
    .Declare(SyntaxGenerator.StringType.Nullable().Variable(thing.Identifier))
    .Add(writeLine.Invocation([SyntaxGenerator.Literal("Enter some things:")]))
    .Do(thing.NotEqual(SyntaxGenerator.Literal("exit")))
        .Add(thing.Assign(console.Access("ReadLine").Invocation()))
        .Add(console.Access("Write").Invocation([SyntaxGenerator.Literal("Do ")]))
        .Add(writeLine.Invocation([thing]))
        .End()
    .End();

6.3 生成的代码

csharp 复制代码

void DoSTh()
{
    string? thing;
    Console.WriteLine("Enter some things:");
    do
    {
        thing = Console.ReadLine();
        Console.Write("Do ");
        Console.WriteLine(thing);
    }
    while (thing != "exit");
}

五、生成类完整的Case

SyntaxGenerator.Create用于组装类的成员

1. 简化方式

csharp 复制代码

var type = SyntaxFactory.ClassDeclaration("UserId")
    .Public()
    .Partial();
var original = SyntaxFactory.IdentifierName("original");
var _original = SyntaxFactory.IdentifierName("_original");
var field = SyntaxGenerator.IntType.Field(_original.Identifier)
    .Private()
    .ReadOnly();
var property = SyntaxGenerator.IntType.GetOnlyProperty("Original", _original)
    .Public();
var constructor = type.Constructor(SyntaxGenerator.IntType.Parameter(original.Identifier))
    .Public()
    .ToBuilder()
    .Add(field.ToIdentifierName().Assign(original))
    .End();

var builder = SyntaxGenerator.Create("Models", type, constructor, field, property);
var result = builder.Build();

2 生成的代码

csharp 复制代码

// <auto-generated/>
namespace Models
{
    public partial class UserId
    {
        public UserId(int original)
        {
            _original = original;
        }

        private readonly int _original;
        public int Original
        {
            get
            {
                return _original;
            }
        }
    }
}

六、总结

SyntaxFactory是个很强大的工具

可以生成几乎所有的代码

只是树形结构细节太多影响代码审阅

为此笔者开源项目对部分SyntaxFactory进行简化

dotnet add package Hand.Generators.EasySyntax --version 0.1.0.1-alpha

源码稍后整理再发布