ASP.Net Download File Error: Thread was being aborted

Hi dawsumn,

Refer below code and change as per your file path.

HTML

<asp:GridView ID="grdTaskHistory" runat="server" CssClass="table table-bordered table-condensed table-responsive" AutoGenerateColumns="false"
    ShowHeaderWhenEmpty="true" Style="font-size: smaller; -ms-word-wrap: break-word; word-wrap: break-word; max-width: none; word-break: break-all;">
    <HeaderStyle CssClass="headerRow panel-midnight-blue-header" />
    <Columns>
        <asp:BoundField HeaderText="Execution Date" DataField="STL_EXEC_DT" ItemStyle-Width="20%" />
        <asp:BoundField HeaderText="Executed By" DataField="STL_EXEC_BY" ItemStyle-Width="10%" />
        <asp:BoundField HeaderText="Comments" DataField="STL_COMMENTS" ItemStyle-Width="30%" />
        <asp:BoundField HeaderText="Helpers" DataField="HELPERS" ItemStyle-Width="20%" />
        <asp:TemplateField HeaderText="Document" ItemStyle-Width="20%   ">
            <ItemTemplate>
                <asp:LinkButton runat="server" ID="btnDoc" Text='<%#Eval("DOC_NAME")%>' OnClick="btnDoc_Click"
                    CommandArgument='<%#Eval("STL_DOCUMENT_PATH")%>' />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[] {
            new DataColumn("STL_EXEC_DT"),
            new DataColumn("STL_EXEC_BY"),
            new DataColumn("STL_COMMENTS"),
            new DataColumn("HELPERS"),
            new DataColumn("DOC_NAME"),
            new DataColumn("STL_DOCUMENT_PATH") });
        dt.Rows.Add("03-03-2020", "John Hammond", "", "", "1.pdf", "1.pdf");
        dt.Rows.Add("03-03-2020", "Mudassar Khan", "", "", "1.xlsx", "1.xlsx");
        dt.Rows.Add("03-03-2020", "Suzanne Mathews", "", "", "1.pdf", "1.pdf");
        dt.Rows.Add("03-03-2020", "Robert Schidner", "", "", "1.xlsx", "1.xlsx");
        grdTaskHistory.DataSource = dt;
        grdTaskHistory.DataBind();
    }
}

protected void btnDoc_Click(object sender, EventArgs e)
{
    string PATH_TO_WRITE_TEMP_FILES = "Files";
    string filePath = Server.MapPath("~/" + PATH_TO_WRITE_TEMP_FILES + "/" + (sender as LinkButton).CommandArgument);
    Response.ContentType = ContentType;
    Response.AppendHeader("Content-Disposition", "attachment; filename=" + System.IO.Path.GetFileName(filePath));
    Response.WriteFile(filePath);
    Response.End();
}

VB.Net

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
        If Not Me.IsPostBack Then
            Dim dt As DataTable = New DataTable()
            dt.Columns.AddRange(New DataColumn() {New DataColumn("STL_EXEC_DT"), New DataColumn("STL_EXEC_BY"), New DataColumn("STL_COMMENTS"), New DataColumn("HELPERS"), New DataColumn("DOC_NAME"), New DataColumn("STL_DOCUMENT_PATH")})
            dt.Rows.Add("03-03-2020", "John Hammond", "", "", "1.pdf", "1.pdf")
            dt.Rows.Add("03-03-2020", "Mudassar Khan", "", "", "1.xlsx", "1.xlsx")
            dt.Rows.Add("03-03-2020", "Suzanne Mathews", "", "", "1.pdf", "1.pdf")
            dt.Rows.Add("03-03-2020", "Robert Schidner", "", "", "1.xlsx", "1.xlsx")
            grdTaskHistory.DataSource = dt
            grdTaskHistory.DataBind()
        End If
    End Sub

    Protected Sub btnDoc_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim PATH_TO_WRITE_TEMP_FILES As String = "Files"
        Dim filePath As String = Server.MapPath("~/" & PATH_TO_WRITE_TEMP_FILES & "/" & (TryCast(sender, LinkButton)).CommandArgument)
        Response.ContentType = ContentType
        Response.AppendHeader("Content-Disposition", "attachment; filename=" & IO.Path.GetFileName(filePath))
        Response.WriteFile(filePath)
        Response.End()
    End Sub