Load the assembly and create a skeleton for each type (just 'public class' now)

Decompiler.csproj

@@ -34,6 +34,7 @@
   <ItemGroup>
     <Folder Include="src" />
     <Compile Include="src\AssemblyInfo.cs" />
+    <Compile Include="src\CodeDomBuilder.cs" />
     <Compile Include="src\MainForm.cs" />
     <Compile Include="src\MainForm.Designer.cs" />
     <Compile Include="src\Program.cs" />

src/CodeDomBuilder.cs

@@ -0,0 +1,69 @@
+using System;
+using System.CodeDom;
+using System.CodeDom.Compiler;
+using System.Collections.Generic;
+using System.IO;
+using System.Windows.Forms;
+using Microsoft.CSharp;
+
+using Mono.Cecil;
+
+namespace Decompiler
+{
+	public class CodeDomBuilder
+	{
+		CodeCompileUnit codeCompileUnit = new CodeCompileUnit();
+		Dictionary<string, CodeNamespace> codeNamespaces = new Dictionary<string, CodeNamespace>();
+		
+		public string GenerateCode()
+		{
+			CSharpCodeProvider provider = new CSharpCodeProvider();
+			
+			TextWriter stringWriter = new StringWriter();
+			
+			CodeGeneratorOptions options = new CodeGeneratorOptions();
+			options.BlankLinesBetweenMembers = true;
+			options.BracingStyle = "C";
+			options.ElseOnClosing = true;
+			options.IndentString = "\t";
+			options.VerbatimOrder = true;
+			
+			provider.GenerateCodeFromCompileUnit(codeCompileUnit, stringWriter, options);
+			
+			// Remove the generated comments at the start
+			string code = stringWriter.ToString();
+			while(code.StartsWith("//") || code.StartsWith("\r\n")) {
+				code = code.Remove(0, code.IndexOf("\r\n") + "\r\n".Length);
+			}
+			
+			return code;
+		}
+		
+		public void AddAssembly(AssemblyDefinition assemblyDefinition)
+		{
+			foreach(TypeDefinition typeDef in assemblyDefinition.MainModule.Types) {
+				AddType(typeDef);
+			}
+		}
+		
+		CodeNamespace GetCodeNamespace(string name)
+		{
+			if (codeNamespaces.ContainsKey(name)) {
+				return codeNamespaces[name];
+			} else {
+				// Create the namespace
+				CodeNamespace codeNamespace = new CodeNamespace(name);
+				codeCompileUnit.Namespaces.Add(codeNamespace);
+				codeNamespaces[name] = codeNamespace;
+				return codeNamespace;
+			}
+		}
+		
+		public void AddType(TypeDefinition typeDef)
+		{
+			CodeTypeDeclaration codeType = new CodeTypeDeclaration();
+			codeType.Name = typeDef.Name;
+			GetCodeNamespace(typeDef.Namespace).Types.Add(codeType);
+		}
+	}
+}

src/MainForm.Designer.cs

@@ -43,14 +43,15 @@ namespace Decompiler
 			this.sourceCode.Location = new System.Drawing.Point(12, 12);
 			this.sourceCode.Multiline = true;
 			this.sourceCode.Name = "sourceCode";
-			this.sourceCode.Size = new System.Drawing.Size(266, 223);
+			this.sourceCode.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
+			this.sourceCode.Size = new System.Drawing.Size(736, 665);
 			this.sourceCode.TabIndex = 0;
 			// 
 			// MainForm
 			// 
 			this.AutoScaleDimensions = new System.Drawing.SizeF(9F, 20F);
 			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
-			this.ClientSize = new System.Drawing.Size(290, 247);
+			this.ClientSize = new System.Drawing.Size(760, 689);
 			this.Controls.Add(this.sourceCode);
 			this.Name = "MainForm";
 			this.Text = "Decompiler";

src/Program.cs

@@ -6,6 +6,8 @@
 using System;
 using System.Windows.Forms;
 
+using Mono.Cecil;
+
 namespace Decompiler
 {
 	/// <summary>
@@ -19,7 +21,7 @@ namespace Decompiler
 		[STAThread]
 		private static void Main(string[] args)
 		{
-			string sourceCode = "<Source code>";
+			string sourceCode = Decompile(@"..\..\tests\ClassStructure\bin\Debug\ClassStructure.dll");
 			
 			Application.EnableVisualStyles();
 			Application.SetCompatibleTextRenderingDefault(false);
@@ -28,5 +30,12 @@ namespace Decompiler
 			Application.Run(mainForm);
 		}
 		
+		static string Decompile(string filename)
+		{
+			AssemblyDefinition assembly = AssemblyFactory.GetAssembly(filename);
+			CodeDomBuilder codeDomBuilder = new CodeDomBuilder();
+			codeDomBuilder.AddAssembly(assembly);
+			return codeDomBuilder.GenerateCode();
+		}
 	}
 }