FormView的Items.Count在“插入”视图上返回null

Question

我有一个FormView应返回0,1或2行。当FormView当前视图是ReadOnly（在PageLoad上）或Edit（在postBack上）时，DataItemCount是正确的。但是在Insert视图中（在postBack上），DataItemCount的数量始终为0.如何在Insert视图中保留正确的行数（在postBack上）？

内容页面

<asp:FormView ID="FormView3" ViewStateMode="Enabled"
    OnDatabound="FormView3_DataBound"
    runat="server"
    DataKeyNames="IDeditorLanguage"
    DataSourceID="SqlDataSource_languages">
    <EditItemTemplate>
        html stuff
    </EditItemTemplate>
    <InsertItemTemplate>
        html stuff
    </InsertItemTemplate>
    <ItemTemplate>
        <asp:LinkButton ID="EditButton" runat="server"
            CausesValidation="False" CommandName="Edit" Text="Edit" />
        <asp:LinkButton ID="DeleteButton" runat="server"
            CausesValidation="False" CommandName="Delete" Text="Delete" 
            OnClientClick="return confirm('Are you sure you want to delete this?');"/>
        <asp:LinkButton class="btn btn-default" ID="NewButton"
            runat="server" CausesValidation="False"
            CommandName="New" Text="New" />
    </ItemTemplate>
</asp:FormView>

<asp:label runat="server" ID="languagesNumer"></asp:label>

背后的代码

protected void FormView3_DataBound(object sender, EventArgs e)
{ 
    if (FormView3.DataItemCount == 0)
    {
        languagesNumer.Text = "The number is 0";
    }
    else if (FormView3.DataItemCount == 1)
    {
        languagesNumer.Text = "The number is 1";
    }
    else if (FormView3.DataItemCount == 2)
    {
        languagesNumer.Text = "The number is 2";
    }
}

更新

这就是我解决问题的方法：

  protected void FormView3_DataBound(object sender, EventArgs e)
{  


 if (FormView3.CurrentMode == FormViewMode.ReadOnly)
        {
            numberLanguages = FormView3.DataItemCount;
        }


    if (numberLanguages == 0)
    {
        languagesNumer.Text = "The number is 0";
    }
    else if (numberLanguages == 1)
    {
        languagesNumer.Text = "The number is 1";
    }
    else if (numberLanguages == 2)
    {
        languagesNumer.Text = "The number is 2";
    }
}