Databind a dropdownlist

Question

當我嘗試數據庫dropdownlist，得到這個：system.data.datarowview
我該怎麼做？

string strQuery = "Select Item FROM Calendar Where UserD="Test"; 
SqlConnection myConn; 
SqlDataAdapter sqlDa = new SqlDataAdapter(strQuery,myConn); 
DataTable sqlTa = new DataTable("Test"); 
da.Fill(sqlTa); 
ddlList.DataSource = sqlTa; 
ddlList.DataBind(); 

Answer 1

string strQuery = "Select Item FROM Calendar Where UserD='Test'"; 

注意，你需要使用字符串周圍單引號，因爲在你的代碼，你沒完成有史以來inital字符串，所以代碼的其餘部分剛剛成爲strQuery的一部分。

另外如果您在將來帶回多個字段，那麼當您綁定下拉列表時，您需要指定數據庫中的哪個字段是值，哪些字段是顯示的文本。

ddlList.DataSource = sqlTa; 
ddlList.DataValueField = "ValueFieldFromDatabaseResults"; 
ddlList.DataTextField = "ShownTextFieldFromDatabaseResults"; 
ddlList.DataBind(); 

Answer 2

您需要告訴它哪些字段用作值和文本。

ddlList.DataSource = sqlTa; 
ddlList.DataValueField = "ValueField"; 
ddlList.DataTextField = "TextField"; 
ddlList.DataBind(); 

而且你的SELECT語句缺少」應該是：

"Select Item FROM Calendar Where UserD='Test'" 

一個例子是：

萊恩指出，如果你拉回來一個字段，那麼你可以只這樣做：

 DataTable dtTable = new DataTable(); 

     try 
     { 
      using (SqlConnection sqlConnection = new SqlConnection("Your connection")) 
      { 
       using (SqlCommand sqlCommand = new SqlCommand("Select Item FROM Calendar Where UserD='Test'", sqlConnection)) 
       { 
        sqlConnection.Open(); 

        using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader()) 
        { 
         dtTable.Load(sqlDataReader); 
         sqlDataReader.Close(); 
        } 
       } 
      } 
     } 
     catch (Exception error) 
     { 
      throw error; 
     } 

     ddlList.DataSource = dtTable; 
     ddlList.DataBind(); 

但如果你有更多然後一個領域，那麼你可以這樣做：

 DataTable dtTable = new DataTable(); 

     try 
     { 
      using (SqlConnection sqlConnection = new SqlConnection("Your connection")) 
      { 
       using (SqlCommand sqlCommand = new SqlCommand("Select Item, id FROM Calendar Where UserD='Test'", sqlConnection)) 
       { 
        sqlConnection.Open(); 

        using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader()) 
        { 
         dtTable.Load(sqlDataReader); 
         sqlDataReader.Close(); 
        } 
       } 
      } 
     } 
     catch (Exception error) 
     { 
      throw error; 
     } 

     ddlList.DataSource = dtTable; 
     ddlList.DataValueField = "id"; 
     ddlList.DataTextField = "item"; 
     ddlList.DataBind(); 

Answer 3

試試這個..

ddlList.DataSource = sqlTa;     
ddlList.DataTextField = "class"; 
ddlList.DataBind(); 

添加ddList.Value="somefield"是可選

Answer 4

加入這一行的方式

ddlList.DataSource = sqlTa; 
ddlList.DataValueField = "ValueFieldFromDatabaseResults"; 
ddlList.DataTextField = "ShownTextFieldFromDatabaseResults"; 
ddlList.DataBind(); 

則u錯過

SqlConnection myConn="must add your connection string code here " 

連接字符串

您還沒有打開的連接字符串，以便

添加myconn.open()

爲

SqlConnection myConn="must add your connection string code here " 
`myconn.open()` 
SqlDataAdapter sqlDa = new SqlDataAdapter(strQuery,myConn)