选定索引已更改未触发

Question

选定索引已更改未触发。下拉列表正在初始化，可以滚动到下一个显示下一个选中索引的值，但是没有启用子例程的DropDownList1_SelectedIndexChanged。

Default.aspx的

<asp:DropDownList ID="DropDownList1" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="true" runat="server"></asp:DropDownList> 

Default.aspx.vb

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
    If Not IsPostBack Then 
    Dim connStr, cmdStr As String 
    Dim ds As New DataSet 
    connStr = "connection string works" 
    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 
    End if 
End Sub 
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged 
    Dim datetimesi As String = "01-01-2014 00:00:00" 
    Dim col1si As String = "0" 
    Dim col2si As String = "0" 
    Dim col3si As String = "0" 
    Dim connStr, cmdStr As String 
    connStr = "connection string works" 
    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() 
       Using rdr = cmd.ExecuteReader() 
        While rdr.Read() 
         datetimesi = rdr(0) 
         col1si = rdr(1) 
         col2si = rdr(2) 
         col3si = rdr(3) 
        End While 
        TextBox10.Text = DropDownList1.Text 
        TextBox11.Text = datetimesi 
        TextBox12.Text = col1si 
        TextBox13.Text = col2si 
        TextBox14.Text = col3si 
       End Using 
       cmd.Dispose() 
       conn.Close() 
       conn.Dispose() 
      End Using 
     End Using 
    Catch ex As Exception 
     TextBox1.Text = "ddlSelectedIndexChanged:" & ex.Message 
    End Try 
End Sub 

Answer 1

我改变OnSelectedIndexChanged = “DropDownList1_SelectedIndexChanged” 到OnTextChanged = “DropDownList1_TextChanged”

和

保护小组DropDownList1_TextChanged（ByVal发件人为对象，ByVa l e As System.EventArgs）句柄DropDownList1.TextChanged

它工作。