C# 在GridView上的asp.net中显示文件图标
我无法根据asp.net GridView中的文件扩展名显示文件图标 GridView的结构是 教程是 错误是: 对象引用未设置为对象的实例 在这行代码后面: 下面是我的代码 你能帮我吗 提前感谢您的帮助,非常感谢C# 在GridView上的asp.net中显示文件图标,c#,asp.net,gridview,icons,nested-gridview,C#,Asp.net,Gridview,Icons,Nested Gridview,我无法根据asp.net GridView中的文件扩展名显示文件图标 GridView的结构是 教程是 错误是: 对象引用未设置为对象的实例 在这行代码后面: 下面是我的代码 你能帮我吗 提前感谢您的帮助,非常感谢 <asp:TemplateField> <ItemTemplate> <img alt="" style="cursor: pointer" src="images/plus.png" /> <asp:
<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";
}
RowDataBound上受保护的void(对象发送方,GridViewRowEventArgs e)
{
如果(e.Row.RowType==DataControlRowType.DataRow)
{
字符串根=@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目录=新的DirectoryInfo(根+“/”+文件夹);
FileInfo[]FileInfo=directory.GetFiles(“*.*”,
SearchOption.AllDirectories);
fCount=directory.GetFiles(“*.*”,
SearchOption.AllDirectories)长度;
gvLabel.Text=fCount.ToString();
长尺寸=0;
foreach(目录.GetFiles(根+“/”+文件夹中的字符串文件,
“**”,SearchOption.AllDirectories)
{
size+=新文件信息(file).Length;
}
gvFolder.Text=Math.Round((双精度)大小/(双精度)(1024*1024),
2) .ToString()+“MB”;
链接按钮lnkDownload=
(LinkButton)e.Row.FindControl(“lnkDownload”);
HiddenField hf=(HiddenField)e.Row.FindControl(“HiddenField 1”);
如果(!String.IsNullOrEmpty(lnkDownload.Text))
{
HtmlImage=(HtmlImage)e.Row.FindControl(“文件图像”);
Add(“src”,geticonformfile(hf.Value));
}
gvOrders.DataSource=fileInfo;
gvOrders.DataBind();
}
}
私有字符串geticonformfile(字符串fileText)
{
字符串扩展名=Path.GetExtension(fileText);
extension=extension.Trim('.').ToLower();
返回“~/fileicons/”+扩展名+”.png”;
}
您有一个嵌套的GridView结构,gvOrders
是您的内部GridView。因此,您必须从内部GridView的行中获取LinkButton,如下所示:
protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
GridView gvOrders = (GridView)e.Row.FindControl("gvOrders");
foreach (GridViewRow row in gvOrders.Rows)
{
LinkButton lnkDownload = (LinkButton)row.FindControl("lnkDownload");
HiddenField hf = (HiddenField)row.FindControl("HiddenField1");
if (!String.IsNullOrEmpty(lnkDownload.Text))
{
//... some code
}
}
}
}
你已经读过了吗
(LinkButton)e.Row.FindControl(“lnkDownload”)
如果该控件不存在,可能会返回null,然后在访问它的Text
属性时抛出NRE。您使用的是哪种结构?嵌套还是简单?@Asif.Ali嵌套在您的上述代码中,您的gvOrders
位于嵌套的GridView模板内。@Asif.Ali很抱歉,结构是嵌套的
protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
GridView gvOrders = (GridView)e.Row.FindControl("gvOrders");
foreach (GridViewRow row in gvOrders.Rows)
{
LinkButton lnkDownload = (LinkButton)row.FindControl("lnkDownload");
HiddenField hf = (HiddenField)row.FindControl("HiddenField1");
if (!String.IsNullOrEmpty(lnkDownload.Text))
{
//... some code
}
}
}
}