Question

我是ASP.NET新手。我在我的DetailsView中有这个：

<asp:TemplateField HeaderText="VendorName">
    <InsertItemTemplate>
        <asp:DropDownList id="insertVendorName" datasourceid="VendorSqlDataSource"
            datatextfield="VendorName" DataValueField="VendorID" 
            SelectedValue='<%# Bind("VendorID") %>'
            runat="server" AutoPostBack="true">
            <asp:ListItem Text="Select" Value="-1" />
        </asp:DropDownList>
    </InsertItemTemplate>
    <EditItemTemplate>
        <asp:DropDownList id="updateVendorName" 
        datasourceid="VendorSqlDataSource"  AutoPostBack="true"
        datatextfield="VendorName" DataValueField="VendorID"  
        SelectedValue='<%# Bind("VendorID") %>'     
        runat="server" OnSelectedIndexChanged="ddlVendor_SelectedIndexChanged"  />
    </EditItemTemplate>
</asp:TemplateField>

这是我编辑模式的代码，它将刷新下拉列表。

protected void ddlVendor_SelectedIndexChanged (object sender, EventArgs e)
{
    DropDownList ddlVendor = (DropDownList)DetailsView1.FindControl("updateVendorName");
    DropDownList ddlVendorBU = (DropDownList)DetailsView1.FindControl("VendorBUName");

    /*
    if (DetailsView1.CurrentMode != DetailsViewMode.Edit)
    {
        DropDownList ddlVendor = (DropDownList)DetailsView1.FindControl("insertVendorName");
        int VendorID = Convert.ToInt32(ddlVendor.SelectedValue.ToString());
    }
    else
    {
        DropDownList ddlVendor = (DropDownList)DetailsView1.FindControl("VendorName");
        int VendorID = Convert.ToInt32(ddlVendor.SelectedValue.ToString());
    }
    */

    if (ddlVendorBU != null)
    {
        Response.Write("SelectChanged");
        int VendorID = Convert.ToInt32(ddlVendor.SelectedValue.ToString());
        Response.Write("VendorID: " + VendorID);

        ddlVendorBU.Items.Clear();

        string strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlConnection con = new SqlConnection(strConn);
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "SELECT VendorBUID, VendorBUName FROM dbo.MDF_VendorBU WHERE VendorID = @VendorID";
        cmd.Parameters.AddWithValue("@VendorID", VendorID);
        DataSet objDs = new DataSet();
        SqlDataAdapter dAdapter = new SqlDataAdapter();
        dAdapter.SelectCommand = cmd;
        con.Open();
        dAdapter.Fill(objDs);

        con.Close();

        /*
        if (objDs.Tables[0].Rows.Count > 0)  
        { 
           ddlVendorBU.DataSource = objDs.Tables[0];
           ddlVendorBU.ItemTextField = "VendorBUName";
           ddlVendorBU.ItemValueField = "VendorBUID";
           ddlVendorBU.DataBind(); 
        } 
        */

        if (objDs.Tables[0].Rows.Count > 0)
        {
            foreach (DataRow dr in objDs.Tables[0].Rows)
            {
                ddlVendorBU.Items.Insert(0, new ListItem((dr["VendorBUName"]).ToString(), (dr["VendorBUID"]).ToString() ));
            }
        }
    }
}

正如你在EditItemTemplate中看到的，我有dropdownlist的updateVendorName ID，这个ddl调用ddlVendor_SelectedIndexChange来刷新另一个列表。现在，我想使用相同的代码刷新列表，但在InsertItemTemplate中。由于dropdownlist ID与“insertVendorName”不同，我如何使用相同的ddlVendor_SelectedIndexChange代码，但在插入模式下使用不同的ddl ID（insertVendorName）？如果我让你困惑，请告诉我。

任何有关更好方法的建议都将受到赞赏。提前谢谢！

Answer 1

您可以对两个DDL使用相同的功能。所以你有：

<asp:DropDownList id="insertVendorName" .... OnSelectedIndexChanged="ddlVendor_SelectedIndexChanged" >

现在在函数本身内部，您需要获得对正确DDL的引用，即调用该函数的DDL。这就是sender的用途。

DropDownList ddlVendor = (DropDownList)sender;

Answer 2

简单来说，您应该将事件处理程序中的代码放在单独的函数中并从那里调用它。我会给你一个骨架结构：

protected void ddlVendor_SelectedIndexChanged (object sender, EventArgs e)
{
    MyFunction(sender);
}


protected void ddlInsertVendorName_SelectedIndexChanged (object sender, EventArgs e)
{
    MyFunction(sender);
}

protected void MyFunction(Object sender)
{
    DropDownList ddl = (DropDownList)sender //ddl will contain the ID etc...
    //shared logic here

    if(ddl.ID.equals("ddlVendor"))
    {
        //edit mode
    }
    else 
    {
        //insert mode
    }
}

这个解决方案略好于System Down（否则是很好的解决方案），因为如果一个下拉列表的事件逻辑需要更改，而另一个下拉列表的事件逻辑不需要更改，则必须重新构建代码。

如果单独的函数仅执行共享逻辑，并将特定于上下文的逻辑放在相应的事件处理程序中，那也会更好。这可能需要你让单独的函数返回一些东西。

为ItemTemplate和EditTemplate重用相同的函数

2 个答案: