连接字符串打开时出现“实例失败。”错误 [英] "Instance failure."error when connectionstring open

问题描述

 <   configuration  >  
 <！ -    < configSections> 
< / configSections>    - >   
 < ;   connectionStrings  >  
  <   add     name   =  ConnectionName    providerName   =  System.Data.SqlClient    connectionString   = 数据源= MyServerName;初始目录= MyDatabaceName;集成安全性=真     < span class =code-keyword> /  >  
 <   / connectionStrings  >  
 <   / configuration  >  

 SqlConnection Sqlc =  new  SqlConnection（ConfigurationManager.ConnectionStrings [  connectionName中]的ConnectionString）。 
 

和打开连接的功能：

 OpenConnection的（SQLC）; 
 
  public   bool  OpenConnection（SqlConnection con）
 {
  if （Sqlc.State == System.Data.ConnectionState.Closed）
 Sqlc.Open（）;  //  错误在于：'实例失败' 
 返回  true ; 
} 
 

解决方案

检查初始目录和目录目录之间是否有空间



如果问题仍然存在，请使用以下

< add name =connconnectionstring =Server =。; Database = myDb ; Trusted_Connection = TRUE; providername =System.Data.SqlClient/> 
 

更改服务器名称

< add name =connconnectionstring =Server = MyServerName; Database = myDataBase; Integrated Security = true;的providerName = System.Data.SqlClient的/> 

<configuration>
  <!--<configSections>
  </configSections>-->
  <connectionStrings>
    <add name="ConnectionName" providerName="System.Data.SqlClient" connectionString="Data Source=MyServerName;Initial Catalog=MyDatabaceName;Integrated Security=True"  />
  </connectionStrings>
</configuration>

SqlConnection Sqlc = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionName"].ConnectionString);

and a function to open connection:

OpenConnection(Sqlc);

public bool OpenConnection(SqlConnection con)
{
  if (Sqlc.State == System.Data.ConnectionState.Closed)
      Sqlc.Open();                                 //error is here:' Instance failure'
 return true;
}

解决方案

check whether space is there in between initial and catalog catalog

if still problem persists, use like following

<add name="conn" connectionstring="Server=.;Database=myDb;Trusted_Connection=True;" providername="System.Data.SqlClient" />

change the server name

<add name="conn" connectionstring="Server=MyServerName;Database=myDataBase;Integrated Security=true;" providername="System.Data.SqlClient"/>

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