從sql server獲取數據到文本框錯誤消息

Question

protected void DropDownServerName_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["Database_Shared_NotebookConnectionString"].ConnectionString); 

     conn.Open(); 

     string serverName = DropDownServerName.SelectedValue; 

     string sqlquery = ("SELECT Architecture FROM tblServer WHERE (ServerName = " + serverName + ")"); 

     SqlCommand command = new SqlCommand(sqlquery, conn); 

     txtUpdateArchitecture.Text = command.ExecuteScalar().ToString(); 

     conn.Close(); 
    } 

DropDownServerName已連接到SQL Server使用SqlDataSource顯示ServerName列上的值列表。

當我得到一個名爲「Brad」的選擇值，並且我希望來自Brad的Architecture列的值顯示在文本框中。但是，我得到錯誤說，無效的列名稱「布拉德」。該列假設爲ServerName，而Brad只是ServerName列中的一個值。

Answer 1

試試這個。它應該與單引號一起工作。

string sqlquery = ("SELECT Architecture FROM tblServer WHERE ServerName = '" + serverName + "'"); 

Answer 2

您需要報價在你的服務器名

string sqlquery = ("SELECT Architecture FROM tblServer WHERE (ServerName = '" + serverName + "')"); 

或者更好的是，使用參數化查詢[它是更安全的，針對SQL注入和有趣的字符的字符串，污染你的查詢]

string sqlquery = "SELECT Architecture FROM tblServer WHERE ServerName = @ServerName"; 

SqlCommand command = new SqlCommand(sqlquery, conn); 
command.Parameters.AddWithValue("@ServerName", serverName); 

Answer 3

在WHERE子句中在servername周圍添加''：

... WHERE ServerName = '" + serverName + "' ... 

Answer 4

您可能缺少變量周圍的單引號。試試這個

protected void DropDownServerName_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["Database_Shared_NotebookConnectionString"].ConnectionString); 

     conn.Open(); 

     string serverName = DropDownServerName.SelectedValue; 

     string sqlquery = ("SELECT Architecture FROM tblServer WHERE (ServerName = '" + serverName + "')"); 

     SqlCommand command = new SqlCommand(sqlquery, conn); 

     txtUpdateArchitecture.Text = command.ExecuteScalar().ToString(); 

     conn.Close(); 
    }