如何在c＃中使用updatepanel清除Dropdownlist？ [英] How to clear Dropdownlist with updatepanel in c#?

问题描述

我有drodownlist，复选框中有自动回发的复选框。

Ex

Hi,
I have drodownlist,checkbox with auto postback in Update panel.
Ex

<asp:updatePanel id="UPD1" runat="Server" UpdateMode="Conditional">
<asp:checkbox id="chk1" runat="server" autopostback="True" OnCheckedChanged="chkAllView_CheckedChanged" />
<asp:dropdownList id="ddl1" runat="server"/>

Protected void Page_Load()
{
  if(!IsPostBack)
{
   DataSet Objds1 = ;

  ddl1.dataSource =Objds1;
  ddl1.databind();

}

}

Protected void chk1_CheckedCObject o,sender e)
{
 If(Chk1.Checked){
  ddl.Items.Clear();}
}

下拉列表项目是我点击Checkbox时不清楚。

请让我知道解决方案。

Dropdownlist items is not clear when I click Checkbox.
Please let me know the for Solutions.

推荐答案

这是我用过的，它为我工作.....

This is how i have used, its working for me.....

<div>
       <asp:ScriptManager ID="ScriptManager1" runat="server">
       </asp:ScriptManager>
       <asp:UpdatePanel ID="UpdatePanel1" runat="server">
           <ContentTemplate>
               <asp:CheckBox ID="chk1" runat="server" AutoPostBack="True" OnCheckedChanged="chkAllView_CheckedChanged" />
               <asp:DropDownList ID="ddl1" runat="server" />
           </ContentTemplate>
       </asp:UpdatePanel>
   </div><pre lang="cs">

protected void Page_Load(object sender, EventArgs e)
      {
          if (!IsPostBack)
          {
              List<string> lst = new List<string>();
              lst.Add("praveen");
              lst.Add("nanda");
              lst.Add("pradeep");
              ddl1.DataSource = lst;
              ddl1.DataBind();
          }

      }

      protected void chkAllView_CheckedChanged(object sender, EventArgs e)
      {
          if (chk1.Checked)
          {
              ddl1.Items.Clear();
          }
      }</pre>

<asp:DropDownList ID="DropDownList1"  Width="150"  runat="server"  AutoPostBack="true">
    </asp:DropDownList>

  <form id="form1" runat="server">
    <div>
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
    <asp:updatePanel id="UPD1" runat="Server" UpdateMode="Conditional">
        <ContentTemplate>
            <br />
            <asp:CheckBox ID="chk1" runat="server" AutoPostBack="true" OnCheckedChanged="chkAllView_CheckedChanged" />
            <asp:DropDownList ID="ddl1" runat="server">
            </asp:DropDownList>          
        </ContentTemplate>
</asp:updatePanel>
    </div>
    </form>

protected void Page_Load(object sender, EventArgs e)
        {
            if(!IsPostBack)
            {
                DataSet ds ; //set dataset values here
                ddl1.DataSource=ds;
                ddl1.DataBind();
            }
        }

        protected void chkAllView_CheckedChanged(object sender, EventArgs e)
        {
            if(chk1.Checked)
                ddl1.Items.Clear();
        }

修改如上。

Modify as above.

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