通过T4模板生成代码，运行时实现
关键代码段：Host
using Microsoft.VisualStudio.TextTemplating;
using System;
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks; namespace CodeGenerate.EngineHost
{
public class TextTemplatingEngineHost : ITextTemplatingEngineHost, ITextTemplatingSessionHost
{
public List<string> LocalDlls { get; set; }
public List<string> Namespaces { get; set; }
/// <summary>
/// 模板文件
/// </summary>
public string TemplateFile { get; set; }
/// <summary>
/// 文件扩展名
/// </summary>
public string FileExtension { get; set; }
/// <summary>
/// 文件扩展名
/// </summary>
public Encoding FileEncoding { get; set; }
/// <summary>
/// 错误信息
/// </summary>
public CompilerErrorCollection Errors { get; set; }
public IList<string> StandardAssemblyReferences
{
get
{
LocalDlls.Add(typeof(System.Uri).Assembly.Location);
return LocalDlls;
}
}
public IList<string> StandardImports
{
get
{
Namespaces.Add("System");
return Namespaces;
}
}
/// <summary>
/// 参数传递
/// </summary>
public ITextTemplatingSession Session { get; set; } public bool LoadIncludeText(string requestFileName, out string content, out string location)
{
content = System.String.Empty;
location = System.String.Empty;
if (File.Exists(requestFileName))
{
content = File.ReadAllText(requestFileName);
return true;
}
else
{
return false;
}
}
public object GetHostOption(string optionName)
{
object returnObject;
switch (optionName)
{
case "CacheAssemblies":
returnObject = true;
break;
default:
returnObject = null;
break;
}
return returnObject;
}
public string ResolveAssemblyReference(string assemblyReference)
{
if (File.Exists(assemblyReference))
{
return assemblyReference;
}
string candidate = Path.Combine(Path.GetDirectoryName(this.TemplateFile), assemblyReference);
if (File.Exists(candidate))
{
return candidate;
}
return "";
}
public Type ResolveDirectiveProcessor(string processorName)
{
if (string.Compare(processorName, "XYZ", StringComparison.OrdinalIgnoreCase) == )
{
//return typeof();
}
throw new Exception("Directive Processor not found");
}
public string ResolvePath(string fileName)
{
if (fileName == null)
{
throw new ArgumentNullException("the file name cannot be null");
}
if (File.Exists(fileName))
{
return fileName;
}
string candidate = Path.Combine(Path.GetDirectoryName(this.TemplateFile), fileName);
if (File.Exists(candidate))
{
return candidate;
}
return fileName;
}
public string ResolveParameterValue(string directiveId, string processorName, string parameterName)
{
if (directiveId == null)
{
throw new ArgumentNullException("the directiveId cannot be null");
}
if (processorName == null)
{
throw new ArgumentNullException("the processorName cannot be null");
}
if (parameterName == null)
{
throw new ArgumentNullException("the parameterName cannot be null");
}
return String.Empty;
}
public void SetFileExtension(string extension)
{
FileExtension = extension;
}
public void SetOutputEncoding(System.Text.Encoding encoding, bool fromOutputDirective)
{
FileEncoding = encoding;
}
public void LogErrors(CompilerErrorCollection errors)
{
Errors = errors;
}
public AppDomain ProvideTemplatingAppDomain(string content)
{
return AppDomain.CreateDomain("Generation App Domain");
} public ITextTemplatingSession CreateSession()
{
return this.Session;
}
}
}
Session
using Microsoft.VisualStudio.TextTemplating;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks; namespace CodeGenerate.EngineHost
{
[Serializable]
public class TextTemplatingSession : Dictionary<string, Object>, ITextTemplatingSession, ISerializable
{
public Guid Id { get;private set; } public TextTemplatingSession() : this(Guid.NewGuid())
{
} public TextTemplatingSession(Guid id)
{
this.Id = id;
}
public override int GetHashCode()
{
return Id.GetHashCode();
}
public TextTemplatingSession(SerializationInfo info, StreamingContext context)
: base(info, context)
{
Id = (Guid)info.GetValue("Id", typeof(Guid));
} void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
base.GetObjectData(info, context);
info.AddValue("Id", Id);
} public override bool Equals(object obj)
{
var o = obj as TextTemplatingSession;
return o != null && o.Equals(this);
} public bool Equals(ITextTemplatingSession other)
{
return other != null && other.Id == this.Id;
} public bool Equals(Guid other)
{
return other.Equals(Id);
}
}
}
入口
string templateFileName = "Template/test.tt";
TextTemplatingEngineHost host = new TextTemplatingEngineHost();
Engine engine = new Engine();
//引入本地dll
host.LocalDlls = new List<string>() { AppDomain.CurrentDomain.BaseDirectory.ToString() + "Params.dll" };
//引入命名空间
host.Namespaces = new List<string>() { "Params" };
//模板文件
host.TemplateFile = templateFileName;
//设置输出文件的编码格式
host.SetOutputEncoding(System.Text.Encoding.UTF8, false);
//通过Session将参数传递到模板
EngineHost.TextTemplatingSession keyValuePairs = new EngineHost.TextTemplatingSession();
testType t = new testType() { Name = "" };
keyValuePairs.Add("test", t);
host.Session = keyValuePairs;
//模板
string input = File.ReadAllText(templateFileName);
//执行代码生成
string output = engine.ProcessTemplate(input, host);
//设置文件的输出路径和文件扩展名 ，，根据模板中的设置定义
string outputFileName = string.Concat(
AppDomain.CurrentDomain.BaseDirectory.ToString(), "Output/",
Path.GetFileNameWithoutExtension(templateFileName),
host.FileExtension);
//将生成的文件写入到新位置
File.WriteAllText(outputFileName, output, host.FileEncoding);
if (host.Errors.HasErrors)
{
foreach (CompilerError error in host.Errors)
{
MessageBox.Show(error.ToString());
}
}
tt文件
<#@ template debug="false" hostspecific="false" language="C#" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ assembly name="Params.dll" #>
<#@ import namespace="Params" #>
<#@ parameter type="Params.testType" name="test" #>
<#@ output extension=".cs" #>
<# if(test!=null&&test.Name!=null){#>
<#=test.Name #>
<# } #>
自定义参数
[Serializable]
public class testType
{
public string Name { get; set; }
}