Open (View) PDF file in new Tab when Link clicked in ASP.Net GridView

Hi rvanjare97,

Refer the below example and change as per your requirement.

Database

CREATE TABLE [StudentFiles]
(
    [Id] [int] IDENTITY(1,1) PRIMARY KEY NOT NULL,
    [StudentId] [int] NOT NULL,
    [FileName] [varchar](max) NULL,
    [Path] [nvarchar](max) NULL
)

HTML

Login Page

<table>
    <tr>
        <td>Name</td>
        <td><asp:TextBox ID="txtName" runat="server" /></td>
    </tr>
    <tr>
        <td></td>
        <td><asp:Button Text="Login" runat="server" OnClick="OnLogin" /></td>
    </tr>
</table>

Student File details

<asp:FileUpload ID="FileUpload1" runat="server" />
<asp:Button ID="btnUpload" runat="server" Text="Upload" OnClick="Upload" />
<hr />
<asp:GridView ID="gvFiles" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="FileName" HeaderText="File Name" />
        <asp:TemplateField>
            <ItemTemplate>
                <asp:LinkButton ID="lnkView" runat="server" Text="View" OnClick="ViewFile"
                    CommandArgument='<%# Eval("FileName") %>'></asp:LinkButton>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Namespaces

using System.Configuration;
using System.Data.SqlClient;
using System.IO;

Code

Login Page

protected void OnLogin(object sender, EventArgs e)
{
    // Validate the login with your database code.
    if (txtName.Text == "Student1")
    {
        Session["StudentId"] = 1;
    }
    else
    {
        Session["StudentId"] = 2;
    }

    Response.Redirect("~/CS.aspx");
}

Student File details

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        BindGrid();
    }
}

protected void Upload(object sender, EventArgs e)
{
    string studentId = Session["StudentId"].ToString();
    string fileName = string.Format("{0}_{1}", studentId, Path.GetFileName(FileUpload1.PostedFile.FileName));

    string filePath = "~/Uploads/" + fileName;
    FileUpload1.PostedFile.SaveAs(Server.MapPath(filePath));

    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection conn = new SqlConnection(constr))
    {
        string sql = "INSERT INTO StudentFiles VALUES (@StudentId, @Name, @Path)";
        using (SqlCommand cmd = new SqlCommand(sql, conn))
        {
            cmd.Parameters.AddWithValue("@StudentId", studentId);
            cmd.Parameters.AddWithValue("@Name", fileName);
            cmd.Parameters.AddWithValue("@Path", filePath);
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        }
    }

    Response.Redirect(Request.Url.AbsoluteUri);
}

protected void ViewFile(object sender, EventArgs e)
{
    string url = string.Format("View.aspx?FileName={0}", (sender as LinkButton).CommandArgument);
    string script = "<script type='text/javascript'>window.open('" + url + "')</script>";
    this.ClientScript.RegisterStartupScript(this.GetType(), "script", script);
}

private void BindGrid()
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "SELECT * FROM StudentFiles WHERE StudentId = @StudentId";
            cmd.Parameters.AddWithValue("@StudentId", Session["StudentId"]);
            cmd.Connection = con;
            con.Open();
            gvFiles.DataSource = cmd.ExecuteReader();
            gvFiles.DataBind();
            con.Close();
        }
    }
}

View Page

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string filePath = Server.MapPath("~/Uploads/") + Request.QueryString["FileName"];
        this.Response.ContentType = "application/pdf";
        this.Response.AppendHeader("Content-Disposition;", "attachment;filename=" + Request.QueryString["FileName"]);
        this.Response.WriteFile(filePath);
        this.Response.End();
    }
}

Screenshot