hi how to redirect to another page if UserName and Password is valid?

protected void ValidateUserInfo(string user, string pass)
{
  
    SqlConnection connection = new SqlConnection("YOUR CONNECTION STRING HERE");
    string sql = "SELECT * FROM TableName WHERE UserID = @username AND Password = @password";
    SqlCommand cmd = new SqlCommand(sql,connection);
    cmd.Parameters.AddWithValue("@username", user);
    cmd.Parameters.AddWithValue("@password", pass);
    connection.Open();
 
    DataTable dt = new DataTable();
    SqlDataAdapter ad = new SqlDataAdapter(cmd);
    ad.Fill(dt);
    if (dt.Rows.Count > 0) { //check if the query returns any data
        //Valid Username and Password
        Response.Redirect("Default.aspx");
    }
    else
    {
        Response.Write("INVALID Username and Password, Try Again!");
    }
    connection.Close();   
}
protected void Button1_Click(object sender, EventArgs e)
{
  ValidateUserInfo(TextUserName.Text.Trim(), TextPassword.Text.Trim());
}

Protected Sub ValidateUserInfo(ByVal user As String, ByVal pass As String)
   
    Dim connection As New SqlConnection("YOUR CONNECTION STRING HERE")
    Dim sql As String = "SELECT * FROM TableName WHERE UserID = @username AND Password = @password"
    Dim cmd As New SqlCommand(sql, connection)
    cmd.Parameters.AddWithValue("@username", user)
    cmd.Parameters.AddWithValue("@password", pass)
    connection.Open()
   
    Dim dt As New DataTable()
    Dim ad As New SqlDataAdapter(cmd)
    ad.Fill(dt)
    If dt.Rows.Count > 0 Then
        'check if the query returns any data
        Response.Redirect("Default.aspx")
    Else
        Response.Write("INVALID Username and Password, Try Again!")
    End If
    connection.Close()
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1_Click
    ValidateUserInfo(TextUserName.Text.Trim(), TextPassword.Text.Trim())
End Sub

public void login()
{
string strLoginId;
        string strPassword;
        DataSet oDs = null;
        bool IsRemember = chkRememberMe.Checked;

//this is class file where you will be write your code for get the information to database
   CityBusinessLogics.AdminLogics oAdmin = new CityBusinessLogics.AdminLogics();
        strLoginId = txtUsername.Text.Trim();
        strPassword = txtPassword.Text.Trim();
        HttpCookie OnlineCookie = new HttpCookie("OnlineCookie");

        if (Page.IsValid)
        {
            try
            {
                oDs = oAdmin.ValidateAdminLogin(strLoginId, strPassword);
                if (oDs.Tables[0].Rows.Count <= 0)
                {
                    lblMessage.Text = "Wrong LoginId or Password !!";
                    lblMessage.Visible = true;
                }
                else if (IsRemember)
                {
                    string EnUserName, EnPwd;
                    EnUserName = oAdmin.base64Encode(strLoginId);
                    EnPwd = oAdmin.base64Encode(strPassword);

                    OnlineCookie.Values.Add("UserName", EnUserName);
                    OnlineCookie.Values.Add("Password", EnPwd);
                   

                    Response.Cookies.Add(OnlineCookie);
                    OnlineCookie.Expires = DateTime.Now.AddDays(15);

                    Session["Admin"] = strLoginId;
                   
                 if (Session["Admin"].ToString() == "admin")
                       Response.Redirect("AdminChangePassword.aspx");
                   else
                        Response.Redirect("RoleTask.aspx");

                }
                else
                {
                    //OnlineCookie.Values.Add("UserName",string .Empty);
                    //OnlineCookie.Values.Add("Password", string.Empty);
                    //OnlineCookie.Values.Add("Roles", string.Empty);
                    //Response.Cookies.Add(OnlineCookie);
                    //OnlineCookie.Expires = DateTime.Now.AddMinutes(5);
                    Session["Admin"] = strLoginId;
                   // Session["Roles"] = oDs.Tables[0].Rows[0]["RoleIds"].ToString();
                  if (Session["Admin"].ToString() == "admin")
                      Response.Redirect("AdminChangePassword.aspx");
                   else
                        Response.Redirect("RoleTask.aspx");
                }

            }
            catch
            {
                lblMessage.Text = "Login failed.";
                lblMessage.Visible = true;
            }
        }

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1_Click
  result=  ValidateUser(TextUserName.Text, TextPassword.Text)
if result > 0 then
response.redirect("validpage.aspx")
endif
End Sub
public function validuser(byval user as string,byval pwd as string)
Dim connection As New SqlConnection("YOUR CONNECTION STRING HERE")
dim result as integer
    Dim sql As String = "SELECT count(*)  from TableName WHERE UserID = @username AND Password = @password"
    Dim cmd As New SqlCommand(sql, connection)
with cmd
   Parameters.AddWithValue("@username", user)
   Parameters.AddWithValue("@password", pass)
result=.executescalar()
if result > 0 then
return result
end if
end with
return 0
end function