我该如何解决这个错误？

Question

在C＃中使用实体框架，我得到这个错误：

The entry 'AlMizanEntities' has already been added. (D:\Document\Almizan\AlMizan\C#\AlMizan\bin\Debug\AlMizan.vshost.exe.config line 7)

我的代码：

private void Fraz() 
{ 
    label1.Text = "Fraz ..."; 
    Application.DoEvents(); 

    AlMizanEntities1 ObjAE = new AlMizanEntities1(); 
} 

public partial class AlMizanEntities1 : ObjectContext 
{ 
    /// <summary> 
    /// Initializes a new AlMizanEntities1 object using the connection string found in the 'AlMizanEntities1' section of the application configuration file. 
    /// </summary> 
    // *ERROR* occurs here 
    public AlMizanEntities1() : base("name=AlMizanEntities1", "AlMizanEntities1") 
    { 
     this.ContextOptions.LazyLoadingEnabled = true; 
     OnContextCreated(); 
    } 

    /// <summary> 
    /// Initialize a new AlMizanEntities1 object. 
    /// </summary> 
    public AlMizanEntities1(string connectionString) : base(connectionString, "AlMizanEntities1") 
    { 
     this.ContextOptions.LazyLoadingEnabled = true; 
     OnContextCreated(); 
    } 

    /// <summary> 
    /// Initialize a new AlMizanEntities1 object. 
    /// </summary> 
    public AlMizanEntities1(EntityConnection connection) : base(connection, "AlMizanEntities1") 
    { 
     this.ContextOptions.LazyLoadingEnabled = true; 
     OnContextCreated(); 
    } 
} 

Answer 1

删除line 7在D:\Document\Almizan\AlMizan\C#\AlMizan\App.config 或删除重复的行其他地方在该文件中。