Question

我已经使用SQL语句中的值填充了DropDownList，但它可以正常工作。

   Try
        cmdStr = "SELECT [idt],[col1] FROM [test];"
        Using conn As New SqlConnection(connStr)
            Using cmd As New SqlCommand(cmdStr, conn)
                conn.Open()
                cmd.ExecuteNonQuery()
                Using da As New SqlDataAdapter(cmd)
                    da.Fill(ds)
                    DropDownList1.DataSource = ds.Tables(0)
                    DropDownList1.DataTextField = "idt"
                    DropDownList1.DataValueField = "col1"
                    DropDownList1.DataBind()
                End Using
                cmd.Dispose()
                conn.Close()
                conn.Dispose()
            End Using
        End Using
    Catch ex As Exception
        TextBox1.Text = ex.Message
    End Try

问题是SQL列表以idt = 68开头，它在DropDownList中显示，但DropDownList1.DataTextField =“”而不是68以下。

     Try
        cmdStr = "SELECT [datetime],[col1],[col2],[col3] FROM [test] WHERE [idt]=@idt;"
        Using conn As New SqlConnection(connStr)
            Using cmd As New SqlCommand(cmdStr, conn)
                conn.Open()
                cmd.Parameters.AddWithValue("@idt", DropDownList1.DataTextField)
                cmd.ExecuteNonQuery()
      ...

Answer 1

更新它以使用DropDownList1.SelectedItem.Text

Try
        cmdStr = "SELECT [datetime],[col1],[col2],[col3] FROM [test] WHERE [idt]=@idt;"
        Using conn As New SqlConnection(connStr)
            Using cmd As New SqlCommand(cmdStr, conn)
                conn.Open()
                cmd.Parameters.AddWithValue("@idt", DropDownList1.SelectedItem.Text)
                cmd.ExecuteNonQuery()

Answer 2

 DropDownList1.DataSource = ds.Tables(0)
 DropDownList1.DataTextField = "idt"
 DropDownList1.DataValueField = "idt"
 DropDownList1.DataBind();

您不需要选择＆＃34; col1＆＃34;专栏。因为你不能使用它。

然后

使用SelectedValue属性

 cmd.Parameters.AddWithValue("@idt", DropDownList1.SelectedValue);

Answer 3

检查DataValueField，DataTextField

DataValueField=will be id for that field/id whenever your search or do any operation
DataTextField= text for that field/id to show on UI.

我想这会起作用

      DropDownList1.DataTextField = "col1"
      DropDownList1.DataValueField = "idt"

DropDownList显示SQL值

3 个答案: