1
我無法根據asp.net GridView中的文件擴展名顯示文件圖標。在GridView上顯示asp.net中的文件圖標
的GridView的結構nested
該教程是Displays file icons in asp.net
錯誤是:
對象引用不設置爲一個對象
在這種的一個實例代碼行:
if (!String.IsNullOrEmpty(lnkDownload.Text))
我的代碼如下。
你能幫我嗎?
預先感謝您的任何幫助,真的很感激。
<asp:TemplateField>
<ItemTemplate>
<img alt="" style="cursor: pointer" src="images/plus.png" />
<asp:Panel ID="pnlOrders" runat="server" Style="display: none">
<asp:GridView ID="gvOrders" runat="server"
AutoGenerateColumns="false" CssClass="mGrid" Width="700"
HorizontalAlign="Center">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<img id="fileImage" runat="server" src="" />
<asp:HiddenField ID="HiddenField1"
runat="server" Value='<%# Eval("Name") %>' />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Download" ItemStyle-
HorizontalAlign="Justify">
<ItemTemplate>
<asp:LinkButton ID="lnkDownload" Text='<%#
Eval("Name") %>' CommandArgument=
'<%# Eval("FullName") %>' runat="server"
OnClick="lnkDownload_Click"
OnClientClick="if (!confirm('Confirm ?'))
return false;"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</asp:Panel>
</ItemTemplate>
</asp:TemplateField>
protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
string root = @FilePath;
string folder = GridView2.DataKeys[e.Row.RowIndex].Value.ToString();
GridView gvOrders = (GridView)e.Row.FindControl("gvOrders");
Label gvLabel = (Label)e.Row.FindControl("gvLabel");
Label gvFolder = (Label)e.Row.FindControl("gvFolder");
DirectoryInfo directory = new DirectoryInfo(root + "/" + folder);
FileInfo[] fileInfo = directory.GetFiles("*.*",
SearchOption.AllDirectories);
fCount = directory.GetFiles("*.*",
SearchOption.AllDirectories).Length;
gvLabel.Text = fCount.ToString();
long size = 0;
foreach (string file in Directory.GetFiles(root + "/" + folder,
"*.*", SearchOption.AllDirectories))
{
size += new FileInfo(file).Length;
}
gvFolder.Text = Math.Round((double)size/(double)(1024 * 1024),
2).ToString() + " MB";
LinkButton lnkDownload =
(LinkButton)e.Row.FindControl("lnkDownload");
HiddenField hf = (HiddenField)e.Row.FindControl("HiddenField1");
if (!String.IsNullOrEmpty(lnkDownload.Text))
{
HtmlImage image = (HtmlImage)e.Row.FindControl("fileImage");
image.Attributes.Add("src", GetIconForFile(hf.Value));
}
gvOrders.DataSource = fileInfo;
gvOrders.DataBind();
}
}
private string GetIconForFile(string fileText)
{
string extension = Path.GetExtension(fileText);
extension = extension.Trim('.').ToLower();
return "~/fileicons/" + extension + ".png";
}
你看過http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-我已經修好了嗎? '(LinkButton)e.Row.FindControl(「lnkDownload」)'如果控件不存在則返回null,然後在訪問它的'Text'屬性時拋出NRE。 –
你正在使用哪種結構?嵌套或簡單? – AsifAli72090
@ Asif.Ali嵌套 –