在Dropdownlist上显示Gridview SQLDatasource选择的索引已更改

Question

我正在尝试使用针对下拉列表更改的下拉列表选定索引的查询从sql数据库显示gridview。

以下是我目前的代码，我认为应该可行：

我没有收到任何错误，当我从下拉列表中选择一个包时，gridview就不会出现。

C＃：

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        DropDownList1.Items.Clear();
        DropDownList1.Items.Add(new ListItem("Select Package", "Select Package"));
        DropDownList1.AppendDataBoundItems = true;
        String strConnString = ConfigurationManager
        .ConnectionStrings["connectionString"].ConnectionString;
        String strQuery = "select distinct Package_Name from dbo.PackageDetail";
        SqlConnection con = new SqlConnection(strConnString);
        SqlCommand cmd = new SqlCommand();
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = strQuery;
        cmd.Connection = con;
        try
        {
            con.Open();
            DropDownList1.DataSource = cmd.ExecuteReader();
            DropDownList1.DataTextField = "Package_Name";
            DropDownList1.DataBind();
            con.Close();
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            con.Close();
            con.Dispose();
        }
    }

}


protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        SqlDataSource SqlDataSource1 = new SqlDataSource();
        SqlDataSource1.ID = "SqlDataSource1";
        this.Page.Controls.Add(SqlDataSource1);
        SqlDataSource1.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["datarepConnectionString"].ConnectionString;
        SqlDataSource1.SelectCommand = "SELECT [ID], [PartNumber], [Qty], [PartDescription], [PR1], [PR2], [PR3], [EXTPR2], [EXTPR1], [EXTPR3] FROM [PackageDetail] where [Package_Name] = '" + DropDownList1.Text + "' ";
        GridView1.DataSource = SqlDataSource1;
        GridView1.DataBind();
    }
}

ASP.NET：

       <asp:DropDownList ID="DropDownList1" runat="server" onselectedindexchanged="DropDownList1_SelectedIndexChanged" AutoPostBack="True" EnableViewState="true" >
                    </asp:DropDownList>
                </center>
                <p>&nbsp;</p>
                <p>
                    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" BackColor="White" BorderColor="#DEDFDE" BorderStyle="None" BorderWidth="1px" CellPadding="4" DataKeyNames="ID" ForeColor="Black" GridLines="Vertical" AllowSorting="True" Height="160px" Width="374px" EnableViewState="true" >
                        <AlternatingRowStyle BackColor="White" />
                        <Columns>
                            <asp:BoundField DataField="ID" HeaderText="ID" InsertVisible="False" ReadOnly="True" SortExpression="ID" />
                            <asp:BoundField DataField="PartNumber" HeaderText="PartNumber" SortExpression="PartNumber" />
                            <asp:BoundField DataField="PartDescription" HeaderText="PartDescription" SortExpression="PartDescription" />
                            <asp:BoundField DataField="Qty" HeaderText="Qty" SortExpression="Qty" />
                            <asp:BoundField DataField="PR1" HeaderText="PR1" SortExpression="PR1" />
                            <asp:BoundField DataField="PR2" HeaderText="PR2" SortExpression="PR2" />
                            <asp:BoundField DataField="PR3" HeaderText="PR3" SortExpression="PR3" />
                            <asp:BoundField DataField="EXTPR2" HeaderText="EXTPR2" SortExpression="EXTPR2" />
                            <asp:BoundField DataField="EXTPR1" HeaderText="EXTPR1" SortExpression="EXTPR1" />
                            <asp:BoundField DataField="EXTPR3" HeaderText="EXTPR3" SortExpression="EXTPR3" />
                        </Columns>
                        <FooterStyle BackColor="#CCCC99" />
                        <HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" />
                        <PagerStyle BackColor="#F7F7DE" ForeColor="Black" HorizontalAlign="Right" />
                        <RowStyle BackColor="#F7F7DE" />
                        <SelectedRowStyle BackColor="#CE5D5A" Font-Bold="True" ForeColor="White" />
                        <SortedAscendingCellStyle BackColor="#FBFBF2" />
                        <SortedAscendingHeaderStyle BackColor="#848384" />
                        <SortedDescendingCellStyle BackColor="#EAEAD3" />
                        <SortedDescendingHeaderStyle BackColor="#575357" />
                    </asp:GridView>

非常感谢帮助。谢谢。