排序是未处理的，即使我有一个处理程序

我正在从SQL Server中提取数据，并将其显示在网格视图中。然后我试图通过点击标题来对列进行排序。我遇到了未处理事件的问题。。。。任何帮助都将是伟大的感谢

我遇到的问题是，当我点击一个标题来整理表格时，我会得到以下错误

一般错误

GridView"_propertyGridView"引发了未处理的事件Sorting。

来源错误：

在执行当前web请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪来识别有关异常的起源和位置的信息。

标记

<asp:GridView ID="_propertyGridView" runat="server" CssClass="table table-hover table-striped" AutoGenerateColumns="false" AllowSorting="true" GridLines="None" OnRowCommand="PropertyRowCommand"  Width="100%">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Ref" SortExpression="Id" HeaderStyle-HorizontalAlign="Left"   />
        <asp:BoundField DataField="PostCode" HeaderText="Post Code" SortExpression="PostCode" HeaderStyle-HorizontalAlign="Left" />
        <asp:BoundField DataField="ContractsFinishedOn" HeaderText="Contract Signed On" SortExpression="ContractsFinishedOn" HeaderStyle-HorizontalAlign="Left" />
        <asp:BoundField DataField="FirstName" HeaderText="First Name" SortExpression="FirstName" HeaderStyle-HorizontalAlign="Left" />
        <asp:BoundField DataField="LastName" HeaderText="Last Name" SortExpression="LastName" HeaderStyle-HorizontalAlign="Left" />
        <asp:BoundField DataField="Mobile" HeaderText="Mobile No." SortExpression="Mobile" HeaderStyle-HorizontalAlign="Left" />
        <asp:BoundField DataField="LandLordEmail" HeaderText="Owners Email" SortExpression="LandLordEmail" HeaderStyle-HorizontalAlign="Left" />
        <asp:BoundField DataField="MoveInDate" HeaderText="Move In Date" SortExpression="MoveInDate" HeaderStyle-HorizontalAlign="Left" />
        <asp:TemplateField HeaderText="Status" SortExpression="Status1">
            <ItemTemplate>
                <asp:CheckBox ID="_tenantPaymentCheckBox" runat="server" Enabled="false" Checked='<%#Bind("TenantReceipt") %>' />
                <asp:LinkButton ID="_tenantPaymentLink" Text="Send Tenant Receipt" CommandArgument='<%#Bind("Id") %>' CommandName="TenantEmail" runat="server" OnClientClick="javascript:return confirm('This will email &amp; sms the tenant, please make sure its correct');" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Status" SortExpression="Status2">
            <ItemTemplate>
                <asp:CheckBox ID="_landlordInfoCheckBox" runat="server" Enabled="false" Checked='<%#Bind("LandlordInfo") %>' />
                <asp:LinkButton ID="_landlordInfoLink" Text="Request Landlord Info" CommandArgument='<%#Bind("Id") %>' CommandName="LandlordInfoEmail" runat="server" OnClientClick="javascript:return confirm('This will email &amp; sms the landlord, please make sure its correct');" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Status" SortExpression="Status3">
            <ItemTemplate >
                <asp:CheckBox ID="_landlordRentCheckBox" runat="server" Enabled="false" Checked='<%#Bind("LandlordReceipt") %>' />
                <asp:LinkButton ID="_landlordRentLink" Text="Send Landlord Receipt" CommandArgument='<%#Bind("Id") %>' CommandName="LandlordEmail" runat="server" OnClientClick="javascript:return confirm('This will email &amp; sms the landlord, please make sure its correct');" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

代码隐藏

protected void _propertyGridView_Sorting(object sender, GridViewSortEventArgs e)
{
    try
    {
        string sortExpression = e.SortExpression;
        ViewState["z_sortexpresion"] = e.SortExpression;
        if (GridViewSortDirection == SortDirection.Ascending)
        {
            GridViewSortDirection = SortDirection.Descending;
            SortGridView(sortExpression, "DESC");
        }
        else
        {
            GridViewSortDirection = SortDirection.Ascending;
            SortGridView(sortExpression, "ASC");
        }
    }
    catch (Exception ex)
    {
        SearchErrorLbl.Text = "error in such";
    }
}
public SortDirection GridViewSortDirection
{
    get
    {
        if (ViewState["sortDirection"] == null)
            ViewState["sortDirection"] = SortDirection.Ascending;
        return (SortDirection)ViewState["sortDirection"];
    }
    set
    {
        ViewState["sortDirection"] = value;
    }
}
private void SortGridView(string sortExpression, string direction)
{
    DTSorting = new DataView(DTSorting, "", sortExpression + " " + direction, DataViewRowState.CurrentRows).ToTable();
    _propertyGridView.DataSource = DTSorting;
    _propertyGridView.DataBind();
}
public DataTable DTSorting
{
    get
    {
        if (ViewState["Sorting"] != null)
            return (DataTable)ViewState["Sorting"];
        else
            return null;
    }
    set
    {
        ViewState["Sorting"] = value;
    }
}

<asp:GridView OnSorting="_propertyGridView_Sorting" ...>
  ...
</asp:GridView>