我刚接触ASP.NET
这个论坛的某位用户帮助我解决了使用用户控件使下拉列表正常工作的问题，现在已经能够正常运行。
在我的用户控件文件VendorListControl.ascx中，我有以下代码。请假设VendorListControl.ascx.cs已经正确工作，也就是当我选择一个VendorName时，它会触发"ddlVendor_SelectedIndexChanged"来刷新"ddlVendorBUList"下拉列表。
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="VendorListControl.ascx.cs" Inherits="MyNamespace.VendorListControl" %>
<asp:DropDownList runat="server" ID="ddlVendorList" onselectedindexchanged="ddlVendor_SelectedIndexChanged" AutoPostBack="True" />
<asp:DropDownList runat="server" ID="ddlVendorBUList" AutoPostBack="True" />
<asp:Label runat="server" ID="lblMessage" />
以下是我的VendorListControl.ascx.cs代码：
using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
namespace MyNamespace
{
public partial class VendorListControl : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
FillVendors();
}
}
protected void ddlVendor_SelectedIndexChanged(object sender, EventArgs e)
{
int VendorID = Convert.ToInt32(ddlVendorList.SelectedValue.ToString());
FillVendorBU(VendorID);
}
private void FillVendors()
{
string strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
System.Data.SqlClient.SqlConnection conn = new System.Data.SqlClient.SqlConnection(strConn);
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandType = CommandType.Text;
cmd.CommandText = "SELECT VendorID, VendorName FROM MDF_Vendor";
DataSet objDs = new DataSet();
SqlDataAdapter dAdapter = new SqlDataAdapter();
dAdapter.SelectCommand = cmd; ;
conn.Open();
dAdapter.Fill(objDs);
conn.Close();
if (objDs.Tables[0].Rows.Count > 0)
{
this.ddlVendorList.DataSource = objDs.Tables[0];
this.ddlVendorList.DataTextField = "VendorName";
this.ddlVendorList.DataValueField = "VendorID";
this.ddlVendorList.DataBind();
this.ddlVendorList.Items.Insert(0, "-- Select --");
}
else
{
this.lblMessage.Text = "No Vendor Found";
}
}
private void FillVendorBU(int VendorID)
{
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)
{
ddlVendorBUList.DataSource = objDs.Tables[0];
ddlVendorBUList.DataTextField = "VendorBUName";
ddlVendorBUList.DataValueField = "VendorBUID";
ddlVendorBUList.DataBind();
ddlVendorBUList.Items.Insert(0, "--Select--");
}
else
{
lblMessage.Text = "No states found";
}
}
}
}
接下来，在我的CreateNewRecord.aspx页面中，我使用以下代码来包含来自用户控件的下拉列表。我可以看到下拉列表正常工作。
<%@ Register TagPrefix="uc" TagName="VendorListControl" Src="Controls/VendorListControl.ascx" %>
// Some where in the form
<tr>
<td class="right" width="20%">Vendor Name:</td>
<td>
<uc:VendorListControl runat="server" />
</td>
</tr>
问题与这两个下拉列表的ID有关。当我尝试插入记录时，似乎无法检测到“ddlVendorList”和“ddlVendorBUList”的ID来自用户控件ascx页面。错误提示：“当前上下文中不存在‘ddlVendorList’的名称”。
ExecuteInsert(ddlVendorList.SelectedItem.Text,
ddlVendorBUList.SelectedItem.Text,
MDFAmount.Text,
StartDate.Text,
EndDate.Text,
VendorQuarter.Text,
MDFName.Text,
MDFSummary.Text,
Status.SelectedItem.Text,
CreatedBy.Value
);
Response.Write("<b>Record was successfully added!</b>");
我知道我对ASP.NET还很陌生，请帮忙。