與SQL Server建立連接時發生網絡相關或特定於實例的錯誤

Question

我只想循環訪問數據庫中的結果。這就是我想要做的所有事情！這是我的錯誤，當我嘗試調試：

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

它指出，這條線：

// fill dataset into named table 
myAdapter.Fill(myDataSet, "Sent"); 

這裏是我的全部代碼：

// get connection strings from app.config 
    string conString = ConfigurationManager.ConnectionStrings["Database1ConnectionString"].ConnectionString; 

    // connection object 
    SqlConnection myConn = new SqlConnection(conString); 

    // create adapter 
    SqlDataAdapter myAdapter = new SqlDataAdapter("select * from `Sent`", myConn); 

    // create command builder 
    SqlCommandBuilder myCommandBuilder = new SqlCommandBuilder(myAdapter); 

    // create dataset 
    DataSet myDataSet = new DataSet(); 

    // fill dataset into named table 
    myAdapter.Fill(myDataSet, "Sent"); 

    // query using linq 
    IEnumerable<DataRow> results 
     = from row in myDataSet.Tables["Sent"].AsEnumerable() 
      select row; 

    // enumerate through results 
    foreach (DataRow row in results) 
    { 
     MessageBox.Show(row.ToString()); 
    } 

我能做些什麼解決這個問題？另外，如果任何人在C＃中使用數據庫更簡單，我會接受你的想法，因爲這對我來說很荒謬（在C＃中操作數據庫）。感謝您的幫助。

更新12年6月29日：

下面的代碼對我的作品：

 // get connection strings from app.config 
     string conString = ConfigurationManager.ConnectionStrings["Database1ConnectionString"].ConnectionString; 

     // connection object 
     SqlCeConnection myConn = new SqlCeConnection(conString); 

     // create adapter 
     SqlCeDataAdapter myAdapter = new SqlCeDataAdapter("select * from [Sent]", myConn); 

     // create command builder 
     SqlCeCommandBuilder myCommandBuilder = new SqlCeCommandBuilder(myAdapter); 

     // create dataset 
     DataSet myDataSet = new DataSet(); 

     // fill dataset into named table 
     myAdapter.Fill(myDataSet, "Sent"); 

     // create new row 
     DataRow newRow = myDataSet.Tables["Sent"].NewRow(); 

     // set field vals 
     newRow["sendTo"] = sendTo; 
     newRow["subject"] = subject; 
     newRow["message"] = message; 

     // add new row to table 
     myDataSet.Tables["Sent"].Rows.Add(newRow); 

     // update database 
     myAdapter.UpdateCommand = myCommandBuilder.GetUpdateCommand(); 
     int updatedRows = myAdapter.Update(myDataSet, "Sent"); 
     //MessageBox.Show("There were "+updatedRows.ToString()+" updated rows"); 

     // close connection 
     myConn.Close(); 

Answer 1

我沒有使用正確的代碼（它沒有任何與任何連接東西做）。這是我第一次試圖用PHP以外的語言連接到數據庫。現在，我可能會使用LINQ或Lambda表達式而不是此代碼。但這裏是我使用哪些工作：

// get connection strings from app.config 
    string conString = ConfigurationManager.ConnectionStrings["Database1ConnectionString"].ConnectionString; 

    // connection object 
    SqlCeConnection myConn = new SqlCeConnection(conString); 

    // create adapter 
    SqlCeDataAdapter myAdapter = new SqlCeDataAdapter("select * from [Sent]", myConn); 

    // create command builder 
    SqlCeCommandBuilder myCommandBuilder = new SqlCeCommandBuilder(myAdapter); 

    // create dataset 
    DataSet myDataSet = new DataSet(); 

    // fill dataset into named table 
    myAdapter.Fill(myDataSet, "Sent"); 

    // create new row 
    DataRow newRow = myDataSet.Tables["Sent"].NewRow(); 

    // set field vals 
    newRow["sendTo"] = sendTo; 
    newRow["subject"] = subject; 
    newRow["message"] = message; 

    // add new row to table 
    myDataSet.Tables["Sent"].Rows.Add(newRow); 

    // update database 
    myAdapter.UpdateCommand = myCommandBuilder.GetUpdateCommand(); 
    int updatedRows = myAdapter.Update(myDataSet, "Sent"); 
    //MessageBox.Show("There were "+updatedRows.ToString()+" updated rows"); 

    // close connection 
    myConn.Close(); 

Answer 2

首先：檢查你的連接字符串錯誤直接告訴你「嘿，我無法連接到您的數據庫「

第二個：select * from Sent（不帶撇號）

Answer 3

這種錯誤會出現，當我們沒有改變在SQL Server配置的TCP/IP設置manager.So we need enable the tcp/ip property to resolve this error

Answer 4

可能說明明顯，但在這裏你檢查了SQLEXPRESS服務正在運行？

https://stackoverflow.com/a/4650231/1095373

Answer 5

您是否更改了您在安裝SQL服務器的機器中使用的密碼？我以前遇到過這種情況，而我所做的是將我的新密碼反映到SQL Server配置中，然後重新啓動服務。

另請確保在SQL配置設置中啓用了TCP/IP設置。