指定的参数(参数名: index)已超出有效值的范围

下面是页面代码:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" Height="289px" Width="760px" GridLines="None" OnRowCommand="GridView1_RowCommand" DataKeyNames="DIA_ID" AllowPaging="True" OnPageIndexChanging="GridView1_PageIndexChanging" CssClass="GridViewStyle" OnRowDataBound="GridView1_RowDataBound1">

     <Columns>
         <asp:TemplateField HeaderText="日志编号" Visible="False">
             <EditItemTemplate>
                 <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("DIA_ID") %>'></asp:TextBox>
             </EditItemTemplate>
             <ItemTemplate>
                 <asp:Label ID="Label1" runat="server" Text='<%# Bind("DIA_ID") %>'></asp:Label>
             </ItemTemplate>
         </asp:TemplateField>
        <asp:BoundField DataField="DIA_DATE" HeaderText="日期" >

下面是后台代码:
protected void GridView1_RowDataBound1(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.Cells[1].Text.Trim().Length > 10)
        {
            e.Row.Cells[1].Text = e.Row.Cells[1].Text.Substring(0, 10);
        }
    }

出现以下异常:指定的参数(参数名: index)已超出有效值的范围。
--------------------编程问答-------------------- if(e.Row.RowType=DataControlRowType.DataRow)
{
if (e.Row.Cells[1].Text.Trim().Length > 10)
        {
            e.Row.Cells[1].Text = e.Row.Cells[1].Text.Substring(0, 10);
        }

}

msn:hxd888666@163.com
hxd888666.cnblogs.com --------------------编程问答-------------------- 兄弟,我用了你的出现了这种错误:
编译器错误信息: CS0029: 无法将类型“System.Web.UI.WebControls.DataControlRowType”隐式转换为“bool”

能帮忙下吗 --------------------编程问答-------------------- 哦,解决了
if(e.Row.RowType=DataControlRowType.DataRow)
{
if (e.Row.Cells[1].Text.Trim().Length > 10)
        {
            e.Row.Cells[1].Text = e.Row.Cells[1].Text.Substring(0, 10);
        }

}
少了个等于符号

补充：.NET技术 ,  ASP.NET