使用的FindControl获得GridView控件在内容页

问题描述

我想找到一个单独的类中的 GridView控件控制和我有问题这样做。我甚至尝试把我的code在aspx.cs页面无济于事。我不断收到对象引用未设置到对象的实例。我敢肯定，有一个简单的步骤我失踪，但在我的研究，我似乎无法找到任何东西。

I would like to find a GridView Control within a separate class and I am having issues doing so. I even tried placing my code in the aspx.cs page to no avail. I keep getting Object reference not set to an instance of an object. I'm sure there is a simple step I'm missing, but in my research I cannot seem to find anything.

  <asp:GridView ID="GridView1" EnableViewState="true" 
    runat="server"  
    BackColor="White" BorderColor="#CC9966"
    BorderStyle="None" BorderWidth="1px" CellPadding="4" Width="933px" 
    onrowdatabound="GridView1_RowDataBound"  
    onrowdeleting="GridView1_RowDeleting" 
    onrowediting="GridView1_RowEditing"
    onrowupdating="GridView1_RowUpdating" 
    onsorting="GridView1_Sorting"
    AllowSorting="true"
    AutoGenerateColumns="False" 
    PersistedSelection="true" onrowcancelingedit="GridView1_RowCancelingEdit">
    <EditRowStyle Font-Size="Small" Width="100px" />
    <FooterStyle BackColor="#FFFFCC" ForeColor="#330099" />
    <Columns>
      <asp:TemplateField>
        <ItemTemplate>
          <asp:LinkButton runat="server" ID="EditLinkButton" CausesValidation="True"
                          Text="Edit" CommandName="Edit"/>
          <asp:LinkButton runat="server" ID="DeleteLinkButton" CausesValidation="False"
                          Text="Delete" CommandName="Delete"/>
        </ItemTemplate>
        <EditItemTemplate>
          <asp:LinkButton runat="server" ID="UpdateLinkButton" CausesValidation="True"
                          Text="Update" CommandName="Update"/>
          <asp:LinkButton runat="server" ID="CancelLinkButton" CausesValidation="False"
                          Text="Cancel" CommandName="Cancel"/>
        </EditItemTemplate>
      </asp:TemplateField>
    </Columns>
  </asp:GridView>

的.cs code

protected void Page_Load(object sender, EventArgs e) {
  SetDirectory();

  System.Web.UI.Page page = (System.Web.UI.Page)System.Web.HttpContext.Current.Handler;
  GridView GridViewCopy = (GridView)page.FindControl("GridView1");

  Log.WriteLine("SortBindGrid: GridView Row Count: " + 
                GridViewCopy.Rows.Count, Log.DEBUG_LEVEL.TERSE);
  return;
}

我试过用MainContent_GridView为查找获取和Master.FindControl所有相同结果的一些变化。

I've tried a few variations of using MainContent_GridView for the find to get and Master.FindControl with all the same result.

推荐答案

在您的意见一个你说明该 GridView控件不在母版页，所以它是安全的假设，它是使用母版页的网页上？因此，它必须是在的ContentPlaceHolder 控制？

In one of your comments you state that the GridView isn't on the Master Page, so is it safe to assume that it's on a page that uses a Master Page? And therefore it must be in a ContentPlaceholder control?

问题的关键是，的FindControl 方法的（强调）：

The key issue is that FindControl method only looks for direct children (emphasis added):

此方法会发现只有如果控制直接由指定的容器中包含一个控制;也就是说，该方法不贯穿的控制层次控件中搜索

所以，你要么需要：

1. 搜索正确的的ContentPlaceHolder 控制中的控制，而不是从页。


2. 循环每一个控件的 Page.Controls 递归，直到你找到你后控制。

1. Search for the control within the correct ContentPlaceholder control, rather than from Page.
2. Loop through each of the Controls in Page.Controls recursively until you find the control you're after.

2的一个例子：

private Control FindControlRecursive(Control rootControl, string controlID)
{
    if (rootControl.ID == controlID) return rootControl;

    foreach (Control controlToSearch in rootControl.Controls)
    {
        Control controlToReturn = 
            FindControlRecursive(controlToSearch, controlID);
        if (controlToReturn != null) return controlToReturn;
    }
    return null;
}

一旦你得到了你的控制，你应该使用它转换为，然后就在这不是很是你所期待的情况下检查空：

Once you've got your control, you should cast it using as and then check for null just in case it's not quite what you were expecting:

var gridView = FindControlRecursively(Page, "GridView1") as GridView

if (null != gridView) {
  // Do Stuff
}

这篇关于使用的FindControl获得GridView控件在内容页的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！