Asp.net 清除复选框列表

在我的“保存”按钮上，我想清除表单中的所有值，我对CheckBoxList执行了以下操作

但它不起作用。为什么呢，它没有明确复选框列表的值

分支是这样填充的：

protected void course_SelectedIndexChanged(object sender, EventArgs e)
{
    try
    {
        int courseId = Convert.ToInt32(course.SelectedValue);
        DataTable dt;
        dt = placementManager.GetBranchList(courseId);
        if (dt.Rows.Count != 0)
        {
            Branch.DataSource = dt;
            Branch.DataTextField = "branch_name";
            Branch.DataValueField = "branch_id";
            Branch.DataBind();                
        }
        Btnsave.Visible = false;
        GridView1.Visible = false;
    }
    catch (Exception ex)
    {
        COMMON.logger.Error("Error on course_SelectedIndexChanged:CompanySelected.aspx.cs", ex);
    }

    if (b)
    {
        gridNotExist.Text = "Records Successfully inserted for the displayed table, To insert new records select new entries";
        this.ViewState.Remove("selectedList");
        this.ViewState.Remove("dt");
        Session.Abandon();
        passout.SelectedIndex = 0;
        company.SelectedIndex = 0;
        txtpackage.Text = "";
        course.SelectedIndex = 0;

        Branch.DataSource = null;
        Branch.DataBind();
        vistDate.Text = "";
        txtvenue.Text = "";
        //GridView1.Visible = true;
    }
}

当然，aspx页面有如下分支：

<asp:UpdatePanel id="update" runat="server">
     <contenttemplate>
         <td>
             <asp:DropDownList ID="course" runat="server" AutoPostBack="True" OnSelectedIndexChanged="course_SelectedIndexChanged" />
             <asp:CustomValidator ID="coursenecessaryForSaveButton" runat="server" ControlToValidate="course" ErrorMessage="Select A Course" OnServerValidate="coursenecessaryForSaveButton_ServerValidate" ValidationGroup="save" />
         </td>
         <td>
             <asp:CustomValidator ID="courseNecessary" runat="server" ErrorMessage="Select A Course" OnServerValidate="courseNecessary_ServerValidate" ValidationGroup="verify" />
         </td>
         <td style="width: 101px">
             Branch Name*
         </td>
         <td style="width: 126px">                        
             <asp:CheckBoxList id="Branch" runat="server" />
         </td>
    </contenttemplate>    
</asp:UpdatePanel>

分支机构名称*

b的定义在哪里

Branch.DataSource = null
Branch.DataBind()

---

您绑定的是什么？？？

给我们更多的代码，您在问题上投入的精力越多，您从我们那里得到的答复就越快，质量也就越好。我像那样编辑了上面的aspx代码，但现在正在发帖。我在更新面板概念方面很差，请对上述代码进行说明。请Bolean b=placedStudentManager.SaveSelectdStudent（gridviewTbl）；b只是在真值和假值的代码上面定义的。cs filedoes update panel不识别td，tr更新panel有问题您问的问题太多了。建议您仔细阅读ASP.NET更新面板-

if (b == true)

Branch.DataSource = null
Branch.DataBind()