在网上做了很多研究后,我仍然对这个问题感到难过.我有一个页面,将名称和类别的数量加载到下拉列表中.我只会这样做！(Page.IsPostBack).当AutoPostBack触发SelectedIndex = 0.我尝试了几种不同的东西.这是我的代码：
页
<form id="AddAssignmentForm" runat="server"> <asp:ScriptManager ID="ScriptManager1" EnablePartialRendering="true" runat="server" /> <asp:UpdatePanel ID="CommentUpdate" runat="server"> <ContentTemplate> Add Comment <asp:DropDownList ID="ddlCategory" runat="server" Width="206" OnSelectedIndexChanged="ddlCategory_SelectedIndexChanged" AutoPostBack="true" /> <asp:TextBox ID="txtName" runat="server" Width="200" /> <asp:TextBox ID="txtAbbrv" runat="server" Width="200" /> <asp:TextBox ID="txtDescription" runat="server" Width="200" Height="90" TextMode="MultiLine" /> </ContentTemplate> </asp:UpdatePanel> </form>
这是后端代码.
private void Page_Load(object sender,System.EventArgs e)
{
if (!Page.IsPostBack)
{
GetCategories();
}
}
public void GetCategories()
{
String strsql = @"SELECT Name,Total
FROM MyTable";
if (con.State == ConnectionState.Closed)
con.Open();
OleDbCommand cmdsql = new OleDbCommand(strsql,con);
OleDbDataReader cmdReader = cmdsql.ExecuteReader();
if (cmdReader.HasRows)
{
while (cmdReader.Read())
{
ddlCategory.Items.Add(new ListItem(cmdReader["Category_Name"].ToString(),cmdReader["Total"].ToString()));
}
ddlCategory.SelectedIndex = -1;
}
cmdReader.Close();
con.Close();
}
public void FillForm(int index)
{
ListItem item = ddlCategory.Items[index];
txtName.Text = item.Text + " " + (Convert.ToInt32(item.Value) + 1).ToString();
txtAbbrv.Text = item.Text.Substring(0,1) + (Convert.ToInt32(item.Value) + 1).ToString();
}
public void ddlCategory_SelectedIndexChanged(Object sender,EventArgs e)
{
//When I break here SelectedIndex always = 1.
FillForm(ddlCategory.SelectedIndex);
}
我只是希望能够根据所选索引填充表单,但我似乎无法得到正确的答案.任何帮助表示赞赏.
解决方法
为下拉列表添加AppendDataBoundItems =“true”
