How to Display User info on Gridview based on who is login?

Make the query such a way that you don't have to write another one. For example,

SELECT * FROM User WHERE Email = @email and Password = @password

This would return all the records that has matched criteria.

Now, on Button_Click or any event of the control,

SqlCommand cmd= new SqlCommand("your query", connectionObject);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);

userGridView.DataSource = dt;
userGridView.DataBind();

You can manipulate this code as per your requirements. This is just the basic idea how you can deal with your problem.

Hope this much is clear to you.
-KR