C#用DesignSurface实现一个简单的窗体设计器

　　System.ComponentModel.Design.DesignSurface是为设计组件提供一个用户界面，通过它可以实现一个简单的窗体设计器。

在构建之前，我们需要引入System.Design.dll，否则会出现找不到DesignSurface的错误。

private void Form1_Load(object sender, EventArgs e)
{
//引用System.Deisgn.dll
DesignSurface ds = new DesignSurface();
//开始加载窗体
ds.BeginLoad(typeof(Form));
Control designerContorl = (Control)ds.View;
designerContorl.Dock = DockStyle.Fill;
this.Controls.Add(designerContorl);
}

运行后出现简单的一个UI设计器



但是该设计器并不能实现控件拖放和UI设计器，以及控件的属性配置。

为了支持从源代码加载初始化窗体，需要对源码中的相关方法进行解析，这里我们 CodeDomDesignerLoader来实现定制化业务，CodeDomDesignerLoader是提供用于实现基于 CodeDOM 的设计器加载程序的基类。

继承它的类需要重写CodeCompileUnit Parse()方法，来实现加载窗体：

protected override CodeCompileUnit Parse()
{

#region 源文件读取
var sw = new StreamReader(@"E:\FrmUser.cs");
var sw_designer = new StreamReader(@"E:\FrmUser.Designer.cs");

string formCodeCS = sw.ReadToEnd();
string formCodeDesigner = sw_designer.ReadToEnd();

List<string> source = new List<string>();
source.Add(formCodeCS);
source.Add(formCodeDesigner);

#endregion
//Rolsyn解析C#
var rootDesigner = Source2CodeDom.Parse(formCodeDesigner);
codeDesingerCompileUnit = Source2CodeDom.GetDesignerCodeComplieUnit(rootDesigner);
var rootCS = Source2CodeDom.Parse(formCodeCS);
codeCSCompileUnit = Source2CodeDom.GetCodeComplieUnit(rootCS);
//MergeFormSource
string mergeS = Source2CodeDom.MergeFormSource(formCodeDesigner, formCodeCS);
codeMergeCompileUnit = Source2CodeDom.GetMergeDesignerCodeComplieUnit(mergeS);
return codeMergeCompileUnit;

解析的方法如下，但是此解析只是用于代码的生成，并不能用户UI界面的显示：

public static CodeCompileUnit GetDesignerCodeComplieUnit2(CompilationUnitSyntax root)
{
CodeCompileUnit ccu = new CodeCompileUnit();
var firstMember = root.Members[0];
var namespaceDeclration = (NamespaceDeclarationSyntax)firstMember;
var designClassDeclaration = (ClassDeclarationSyntax)namespaceDeclration.Members[0];
var myDesignerClass = new CodeTypeDeclaration(designClassDeclaration.Identifier.ToString());
var initializeComponent = new CodeMemberMethod();
var ns = new CodeNamespace(namespaceDeclration.Name.ToString());

foreach (var m in designClassDeclaration.Members)
{

if (m is ConstructorDeclarationSyntax)
{
var ctor = ((ConstructorDeclarationSyntax)m);
var codeBody = ctor.Body.ToString();
codeBody = codeBody.Trim().TrimStart('{').TrimEnd('}').Trim().TrimEnd(';');
CodeSnippetExpression csbody = new CodeSnippetExpression(codeBody);
CodeExpressionStatement stmt = new CodeExpressionStatement(csbody);
//Add the expression statements to the method.
// InitializeComponent
var cctor = new CodeConstructor();
cctor.Name = ctor.Identifier.ToString();
//var cmm = new CodeMemberMethod();
//cmm.Name = ctor.Identifier.ToString();
//cmm.Attributes = GetCtoRAttrMapping(ctor);
//cmm.ReturnType = new CodeTypeReference(typeof(void));
cctor.Statements.Add(stmt);

myDesignerClass.Members.Add(cctor);
}
if (m is FieldDeclarationSyntax)
{
var F = ((FieldDeclarationSyntax)m);
var type = F.Declaration.Type;
foreach (var variable in F.Declaration.Variables)
{
var field = new CodeMemberField();
field.Name = variable.Identifier.ToString();
field.Type = new CodeTypeReference(type.ToString());
field.Attributes = GetFieldAttrMapping(F);
//field.InitExpression = new CodePrimitiveExpression(null);
myDesignerClass.Members.Add(field);
}
}
if (m is MethodDeclarationSyntax)
{
var node = m as MethodDeclarationSyntax;
#region xml comments
var xmlTrivia = node.GetLeadingTrivia()
.Select(i => i.GetStructure())
.OfType<DocumentationCommentTriviaSyntax>()
.FirstOrDefault();

#endregion

var method = (MethodDeclarationSyntax)m;

var cmm = new CodeMemberMethod();
cmm.Name = method.Identifier.ToString();

///XML注释
string[] comments = xmlTrivia.ToString().Split("\r\n".ToCharArray());
foreach (string text in comments)
{
if (text.Trim() != "")
{
cmm.Comments.Add(new CodeCommentStatement(text.Trim().TrimStart("///".ToCharArray()).Trim(), true));
}
}

if (cmm.Name == "InitializeComponent")
{
//region
CodeRegionDirective codeRegion = new CodeRegionDirective(CodeRegionMode.Start, "Windows 窗体设计器生成的代码");
CodeRegionDirective codeEndRegion = new CodeRegionDirective(CodeRegionMode.End, "");

cmm.StartDirectives.Add(codeRegion);
cmm.EndDirectives.Add(codeEndRegion);
}

//MemberAttributes.Family is protected
//cmm.Attributes = MemberAttributes.Override | MemberAttributes.Family;
cmm.Attributes = GetMethodAttrMapping(method);
cmm.ReturnType = new CodeTypeReference(method.ReturnType.ToString());

foreach (var p in method.ParameterList.Parameters)
{
CodeParameterDeclarationExpression cpd = new CodeParameterDeclarationExpression();
cpd.Name = p.Identifier.ToString();

cpd.Type = new CodeTypeReference(p.Type.ToString());

cmm.Parameters.Add(cpd);
}
//包含方法{};，会重复生成{};
string codeBody = method.Body.ToString();
codeBody = codeBody.Trim().TrimStart('{').TrimEnd('}').Trim().TrimEnd(';');
if (codeBody != "")
{
CodeSnippetExpression csbody = new CodeSnippetExpression(codeBody);
CodeExpressionStatement stmt = new CodeExpressionStatement(csbody);
//Add the expression statements to the method.
cmm.Statements.Add(stmt);
}
myDesignerClass.Members.Add(cmm);

}
if (m is MemberDeclarationSyntax)
{

}
}

ccu.Namespaces.Add(ns);

//Partial Class
myDesignerClass.IsPartial = true;

ns.Types.Add(myDesignerClass);

return ccu;
}

窗体的显示，需要逐句进行C#解析，特别是InitializeComponent()方法。





.CS Code其实最简单的就是读取源代码，然后返回就可以了。当设计器添加控件或者绑定事件时，可以通过文本操作进行代码完善。

//直接返回代码，最简单
public string GetTextCSCode()
{
Flush();
return __CSTextCode;
}

CodeDomHostLoader类中有OnComponentRename，在设计器重命名组件时候响应，这里可以修复后台.cs中的控件引用







但此设计器还有很多不完善的地方，后期有时间再完善吧。