我有一个GridView,我需要能够以编程方式更改编辑模板中TextBox的值。当我在onRowDataBound期间尝试访问它时,我得到了这个:
异常详细信息:System.NullReferenceException:未将对象引用设置为对象的实例。
我想在onRowDataBound方法中,无法访问编辑模板控件。但是,当我尝试在onRowEditing方法中编辑TextBox的值时,GridViewEditEventArgs对象没有.Row选项,因此看起来您无法在onRowEditing方法中访问编辑模板中的控件。
如何以编程方式更改GridView编辑模板中TextBox的值?
ASP.NET WebForms,.NET 4.0,C#
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编辑#1:这就是我现在拥有的。在RowEditing中,txtMiles对象最终为null。
<asp:TemplateField HeaderText="Miles Frequency">
<ItemTemplate>
<asp:Label ID="lblFreqMiles" runat="server" Text='<%# Eval("FrequencyMiles") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate >
<asp:TextBox ID="txtFreqMiles" runat="server" Text='<%# Eval("FrequencyMiles")%>' Width="50px"></asp:TextBox>
<asp:RequiredFieldValidator runat="server" ID="req1" ControlToValidate="txtFreqMiles" ErrorMessage="*" />
<asp:CompareValidator ID="CompareValidator1" runat="server" Operator="DataTypeCheck" Type="Integer" ControlToValidate="txtFreqMiles" ErrorMessage="Value must be a whole number." />
</EditItemTemplate>
</asp:TemplateField>
protected void gvMaint_RowEditing(object sender, GridViewEditEventArgs e)
{
//format Miles Frequency column
GridViewRow row = grvMaint.Rows[e.NewEditIndex];
TextBox txtMiles = (TextBox)row.FindControl("txtFreqMiles");
if (txtMiles.Text == "999999")
{
//do stuff
}
grvMaint.EditIndex = e.NewEditIndex;
populateMaintGrid();
}
答案 0 :(得分:4)
在尝试获取控件之前,请确保该行处于编辑模式:
protected void gvMaint_RowDataBound(Object sender, GridViewRowEventArgs e)
{
if(e.Row.RowState == DataControlRowState.Edit)
{
TextBox txtFreqMiles = (TextBox)e.Row.FindControl("txtFreqMiles");
// At this point, you can change the value as normal
txtFreqMiles.Text = "some new text";
}
}