DataTable Distinct Rows : Remove Duplicate Rows from DataTable in C# .Net

 Hi Sir,

I have a doubt...

If a user is uploading files on the dynamic file upload controls by mistake he selectes one file more than once and it gets uploaded to a temp location only once but whereas in the girdview it displays more than once and when the user clicks on the download on the repeated files it those a error is thr is any way so that the user selcts the files only once.... 

Are you confortable of the what I'm asking... 

<asp:Content ID="Content1" ContentPlaceHolderID="cphWorkArea" Runat="Server">
    <h1 class="main-heading" style="height: 9px; margin-left: 521px; width: 368px;">Welcome to Multi-Upload &nbsp;&nbsp;</h1>
    <p style="width: 203px; height: 0px; margin-left: 1040px">
        Welcome
    <asp:Label ID="user" runat="server" Font-Size="Medium"></asp:Label>
    <span style="font-family:Arial"><span style="color: #003366">&nbsp;<asp:Button ID="logout" runat="server" onclick="logout_Click" Text="Logout" />
        </span></span><br />
    </p>
    <h1 class="main-heading" style="height: 1px; margin-left: 521px; width: 374px;">&nbsp;</h1>
    <div id="upload" runat="server">
    <p style="width: 389px; height: 53px; margin-left: 480px">
          
        <br /><br />
        </p>
        <div id = "FileUploadContainer">
            <!--FileUpload Controls will be added here -->
        </div>
        <br />
        <asp:Button ID="btnUpload" runat="server" Text="Upload" OnClick="btnUpload_Click" />
        <br />
        <br />
          
        </div>
    <br />
    <br />
    <br />
     
    <asp:GridView ID="GridView1" runat="server"  BackColor="#EBEBEB"
        AutoGenerateColumns="False" CssClass="full-width grid" Height="268px"
        Width="663px">
        <HeaderStyle BackColor="#CCCCCC" />
          
        <AlternatingRowStyle BackColor="#F7F7F7" />
        <Columns>
            <asp:TemplateField HeaderText="Select">
                <ItemTemplate>
                    <asp:CheckBox ID="CheckBox1" runat="server"/>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField="Name" HeaderText="File Name" />
            <asp:TemplateField ItemStyle-HorizontalAlign="Center"
                HeaderText="Link to download">
                <ItemTemplate>
                    <asp:LinkButton ID="lnkDownload" runat="server" OnClick="DownloadFile"
                        Text='<%# Eval("Path") %>'></asp:LinkButton>
                </ItemTemplate>
  
<ItemStyle HorizontalAlign="Center"></ItemStyle>
            </asp:TemplateField>
            <asp:BoundField DataField="IsExists" HeaderText="Status" />
        </Columns>
    </asp:GridView>
  
    <br />

    
</asp:Content>

protected void btnUpload_Click(object sender, EventArgs e)
    {
        List<ListItem> files = new List<ListItem>();
        for (int i = 0; i < Request.Files.Count; i++)
        {
            HttpPostedFile PostedFile = Request.Files[i];
  
            if (PostedFile.ContentLength > 0)
            {
                string FileName = System.IO.Path.GetFileName(PostedFile.FileName);
                string Ext = System.IO.Path.GetExtension(FileName);
                if ((Ext == ".pptx"))
                {
                    PostedFile.SaveAs(Server.MapPath("~/Temp/") + FileName);
  
                    string[] filePaths = Directory.GetFiles(Server.MapPath("Files\\"));
  
                    string isExists = string.Empty;
  
                    DataTable dt = new DataTable();
                    if (ViewState["Table"] == null)
                    {
                        dt.Columns.AddRange(new DataColumn[3] { new DataColumn("Name",typeof(string)),
                                      new DataColumn("Path",typeof(string)),
                                     new DataColumn("IsExists",typeof(string))});
                    }
                    else
                    {
                        dt = (DataTable)ViewState["Table"];
                    }
  
                    isExists = File.Exists(Server.MapPath("~/Files/") + FileName) ? "Already exists" : "New";
  
                    dt.Rows.Add(FileName, string.Format("~/Temp/{0}", FileName), isExists);
                    ViewState["Table"] = dt;
                    this.GridView1.DataSource = dt;
                    this.GridView1.DataBind();
  
                    //string filePath = Server.MapPath("Files\\") + FileName;
                    //files.Add(Path.GetFileName(FileName), filePath);
                    // files.Add(new ListItem(Path.GetFileName(FileName), filePath));
                    server.Visible = true;
                    upload.Visible = false;
                }
  
                else
                {
                    Response.Write(@"<script language='javascript'>alert('Error in uploading: \n" + FileName + " .');</script>");
                }
  
            }
              
  
             
        }
                  
    }