预备知识：
1、了解反射技术
2、了解C#3.0中扩展方法，分布类，Linq to object,Linq to sql
3、了解ASP.NET MVC
在项目中每添加一个表往往都要添加一套增删改代码，而且这些代码很多情况下都很相似，这里我们给出一个通用的解决方案供大家参考。
一、准备工作：
这里我们先要在数据库中添加两个表News和User如下图：然后拖到dbml中生成实体类。
这里我们先准备一个接口：ICommonTable
Code
public interface ICommonTable
{
int id { get; set; }
}
然后让News和User实体都继承于此接口
Code
public partial class News : ICommonTable
{
}
public partial class User : ICommonTable
{
}
二、通用删除操作
分别添加NewsList.aspx和UserList.aspx两个view，添加方式参见ASP.NET MVC实践系列2-简单应用
在这两个View中加入删除链接：
<%= Html.ActionLink("删除", "Delete", new { key = item.id, partialName="News" })%>
和
<%= Html.ActionLink("删除", "Delete", new { key = item.id, partialName="User" })%>
然后添加一个Controller：
public
ActionResult Delete(
string
partialName,
int
?
key)
{
RepositoryBase repositoryBase = new RepositoryBase(partialName);
repositoryBase.Delete(key ?? 0 );
return RedirectToAction(partialName + " List " ); // 返回到list
}
{
RepositoryBase repositoryBase = new RepositoryBase(partialName);
repositoryBase.Delete(key ?? 0 );
return RedirectToAction(partialName + " List " ); // 返回到list
}
接下来我们介绍一下RepositoryBase ：
{
public Type EntityType { get ; private set ; }
public RepositoryBase( string entityType)
{
Type type = GetBllTypeByName(entityType);
EntityType = type;
}
public ICommonTable CreateNew()
{
return (ICommonTable)Activator.CreateInstance(EntityType);
}
/// <summary>
/// 通过字符串获得其Type
/// </summary>
/// <param name="typeName"></param>
/// <returns></returns>
private static Type GetBllTypeByName( string typeName)
{
Type type = null ;
var ass = AppDomain.CurrentDomain.GetAssemblies()
.Where(p => p.FullName.Contains( " CommonCEDemo " ));
foreach (var a in ass)
{
type = a.GetTypes().Where(p => p.Name == typeName).FirstOrDefault();
if (type != null )
break ;
}
if (type == null )
{
throw new Exception( " 类型未定义: " + typeName);
}
return type;
}
public RepositoryBase(Type entityType)
{
EntityType = entityType;
}
public ICommonTable Get( int id)
{
DBDataContext db = Context.GetContext();
return db.GetTable(EntityType).Cast < ICommonTable > ().FirstOrDefault(p => p.id == id);
}
public void Delete( int id)
{
ICommonTable bllTable = Get(id);
Context.GetContext().GetTable(EntityType).DeleteOnSubmit(bllTable);
Context.GetContext().SubmitChanges();
}
}
这里边重点要理解的就是GetBllTypeByName方法。有了这个方法我们就可以动态的通过名字获得相应的Type了。这里还有个问题就是DataContext是从何而来的，我们这里为了简单起见全程声明了一个DataContext没有考虑多线程的情况
{
static DBDataContext context;
static Context()
{
if (context == null )
{
context = new DBDataContext();
}
}
public static DBDataContext GetContext()
{
return context;
}
}
三、通用增加、修改
首先添加一个CreateEditView.aspx视图
<
asp:Content ID
=
"
Content2
"
ContentPlaceHolderID
=
"
MainContent
"
runat
=
"
server
"
>
<% Html.RenderPartial(ViewData[ " PartialName " ].ToString()); %>
</ asp:Content >
<% Html.RenderPartial(ViewData[ " PartialName " ].ToString()); %>
</ asp:Content >
然后添加两个Partial视图News.ascx和User.ascx，这两个视图是分别基于News和User类的强类型视图，具体内容参加源码。
接下来我们添加相应的Controller
{
ViewData[ " PartialName " ] = partialName;
RepositoryBase repositoryBase = new RepositoryBase(partialName);
ICommonTable table;
if (key == null )
{
table = repositoryBase.CreateNew();
}
else
{
table = repositoryBase.Get(key ?? 0 );
}
return View( " CreateEditView " , table);
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult CreateEditView( string partialName, int ? key, FormCollection formCollection)
{
RepositoryBase repositoryBase = new RepositoryBase(partialName);
ICommonTable bllTable;
if (key == null )
{
bllTable = repositoryBase.CreateNew();
}
else
{
bllTable = repositoryBase.Get(key ?? 0 );
}
this .UpdateModel(bllTable, true );
if (key == null )
{
Context.GetContext().GetTable(repositoryBase.EntityType).InsertOnSubmit(bllTable);
}
Context.GetContext().SubmitChanges();
return RedirectToAction(partialName + " List " ); // 返回到list
}
这里边大家可能有疑问的就是this.UpdateModel(bllTable, true);这个方法在mvc框架中并不存在，这是我添加的扩展方法，这个地方如果使用UpdateModel(bllTable)虽然编译不会报错，但也没有更新成功，查了一下mvc的源码，问题就出在如下源码中：
if (model == null ) {
throw new ArgumentNullException( " model " );
}
if (valueProvider == null ) {
throw new ArgumentNullException( " valueProvider " );
}
Predicate < string > propertyFilter = propertyName => BindAttribute.IsPropertyAllowed(propertyName, includeProperties, excludeProperties);
IModelBinder binder = Binders.GetBinder( typeof (TModel));
ModelBindingContext bindingContext = new ModelBindingContext() {
Model = model,
ModelName = prefix,
ModelState = ModelState,
ModelType = typeof (TModel),
PropertyFilter = propertyFilter,
ValueProvider = valueProvider
};
binder.BindModel(ControllerContext, bindingContext);
return ModelState.IsValid;
}
{
/// <summary>
/// 更新时是否按照当前类型进行更新
/// </summary>
/// <typeparam name="TModel"></typeparam>
/// <param name="controller"></param>
/// <param name="model"></param>
/// <param name="isEx"></param>
public static void UpdateModel < TModel > ( this Controller controller, TModel model, bool isExtension) where TModel : class
{
if (isExtension)
{
Predicate < string > propertyFilter = propertyName => IsPropertyAllowed(propertyName, null , null );
IModelBinder binder = ModelBinders.Binders.GetBinder(model.GetType());
ModelBindingContext bindingContext = new ModelBindingContext()
{
Model = model,
ModelName = null ,
ModelState = controller.ModelState,
ModelType = model.GetType(),
PropertyFilter = propertyFilter,
ValueProvider = controller.ValueProvider
};
binder.BindModel(controller.ControllerContext, bindingContext);
}
else
{
throw new Exception( " isExtension不能选择false " );
}
}
private static bool IsPropertyAllowed( string propertyName, string [] includeProperties, string [] excludeProperties)
{
bool includeProperty = (includeProperties == null ) || (includeProperties.Length == 0 ) || includeProperties.Contains(propertyName, StringComparer.OrdinalIgnoreCase);
bool excludeProperty = (excludeProperties != null ) && excludeProperties.Contains(propertyName, StringComparer.OrdinalIgnoreCase);
return includeProperty && ! excludeProperty;
}
}
四、缺点
1、须要按照规则命名，比方说Partial视图需要以相应的类名来命名
2、页面引用是弱类型的
五、
源码下载
本文转自 你听海是不是在笑 博客园博客，原文链接：http://www.cnblogs.com/nuaalfm/archive/2009/11/11/1600811.html
，如需转载请自行联系原作者
