display record from database(one tire)

your database like
    database name :student
    table name        :tbl_StudentData
    Field name         :id,name,age,gender,city,phone

Your .aspx page
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<div>

   <asp:GridView id="GridView1" runat="server">

   </asp:Gridview>

</div>

--> your .aspx.cs file

--> if you want to display record from table or database that time add following namespace in your code behind file
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using System.Data;

using System.Data.SqlClient;

--> and then create following  object  above page load event
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    SqlConnection cn;

    SqlCommand cmd;

    SqlDataAdapter da;

    DataSet ds;

--> next assign the connection string in page laod event
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cn = new SqlConnection(@"DataSource=\student.mdf;Integrated Security=True;User Instance=True");

--> and then write following code in your code behind on page load event
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 cmd = new SqlCommand("select * from tbl_StudentData", cn);

        da = new SqlDataAdapter(cmd);

        ds = new DataSet();

        da.Fill(ds);

        GridView1.DataSource = ds;   //give dataset to gridview

        GridView1.DataBind();         // binding gridview