FormView.FindControl()：对象引用错误

发布于 2024-08-06 04:14:22 字数 1675 浏览 11 评论 0原文

我有一个 formview，其中 tr/td 中有几个文本框。我试图使用 .FindControl 方法获取文本框，但它返回 null。 FormView 始终处于编辑模式（因此我始终处于 EditItemTemplate 中），并且我尝试将查询字符串值加载到来自上一页的文本框中，因此我确实需要在 page_load 上执行此操作。我总是在 Gridviews 上这样做，像这样：

txtFirstName = (TextBox)fvGeneralInfo.FindControl("txtFirstName");

或像这样：

txtFirstName = (TextBox)fvGeneralInfo.FooterRow.FindControl("txtFirstName");

或像这样：

txtFirstName = (TextBox)fvGeneralInfo.Rows.FindControl("txtFirstName");

什么给出了？

<asp:FormView ID="fvGeneralInfo" runat="server" 
    DataSourceID="objInstructorDetails"
    OnItemCommand="fvGeneralInfo_ItemCommand"
    OnItemUpdated="fvGeneralInfo_ItemUpdated"  
    DefaultMode="Edit"
    DataKeyNames="InstructorID" >
    <EditItemTemplate>
        <table>
            <tr>
                <td colspan="2" class="Admin-SubHeading" style="padding-left:10px;">General Info:</td>
            </tr>
            <tr>
                <td class="Admin-FieldLabel">ID:</td>
                <td><asp:TextBox ID="txtInstructorId" runat="server" CssClass="Admin-Textbox" ReadOnly="true" Text='<%# Bind("InstructorID") %>' /></td>
            </tr>
            <tr>
                <td class="Admin-FieldLabel">First Name:</td>
                <td><asp:Textbox ID="txtFirstName" runat="server" CssClass="Admin-Textbox" Text='<%# Bind("FirstName") %>' /></td>
            </tr>
            </table>  
        </EditItemTemplate>
    </asp:FormView>

原文

I have a formview that has several textboxes inside of tr/td's. I'm trying to get the textboxes by using the .FindControl method but it's coming back null. The FormView is always in Edit mode (so I'm always in the EditItemTemplate) and i'm trying to load querystring values into the textboxes coming from the previous page so I do need this to happen on page_load. I do this on Gridviews all the time like this:

txtFirstName = (TextBox)fvGeneralInfo.FindControl("txtFirstName");

or like this:

txtFirstName = (TextBox)fvGeneralInfo.FooterRow.FindControl("txtFirstName");

or like this:

txtFirstName = (TextBox)fvGeneralInfo.Rows.FindControl("txtFirstName");

What gives?

<asp:FormView ID="fvGeneralInfo" runat="server" 
    DataSourceID="objInstructorDetails"
    OnItemCommand="fvGeneralInfo_ItemCommand"
    OnItemUpdated="fvGeneralInfo_ItemUpdated"  
    DefaultMode="Edit"
    DataKeyNames="InstructorID" >
    <EditItemTemplate>
        <table>
            <tr>
                <td colspan="2" class="Admin-SubHeading" style="padding-left:10px;">General Info:</td>
            </tr>
            <tr>
                <td class="Admin-FieldLabel">ID:</td>
                <td><asp:TextBox ID="txtInstructorId" runat="server" CssClass="Admin-Textbox" ReadOnly="true" Text='<%# Bind("InstructorID") %>' /></td>
            </tr>
            <tr>
                <td class="Admin-FieldLabel">First Name:</td>
                <td><asp:Textbox ID="txtFirstName" runat="server" CssClass="Admin-Textbox" Text='<%# Bind("FirstName") %>' /></td>
            </tr>
            </table>  
        </EditItemTemplate>
    </asp:FormView>

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盗琴音 2024-08-13 04:14:23

abatishchev 的答案是正确的，尽管我发现这种变体更简洁：它避免了显式调用 DataBind() 。

<asp:FormView ID="fvMember" runat="server" DataSourceID="tblMembers" DefaultMode="Insert" OnDataBound="DataBound">...</asp:FormView>

protected void DataBound(object sender, EventArgs e)
{
    if (fvMember.CurrentMode == FormViewMode.Edit)
    {
        Label lblSubmit = fvMember.FindControl("lblSubmit") as Label;
        ...
    }
}

abatishchev's answer is right, although I found this variation a bit neater: it avoids having to call DataBind() explicitly.

<asp:FormView ID="fvMember" runat="server" DataSourceID="tblMembers" DefaultMode="Insert" OnDataBound="DataBound">...</asp:FormView>

protected void DataBound(object sender, EventArgs e)
{
    if (fvMember.CurrentMode == FormViewMode.Edit)
    {
        Label lblSubmit = fvMember.FindControl("lblSubmit") as Label;
        ...
    }
}

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