Return a value from sql

Im trying move my sql connection to a method in a class file and return a value to check if the username existing in the db and display as text in the page to show others that the username exist. How should i modify my aspx .cs page to display error as a label in the aspx code page?

My original code on the aspx .cs page:

        string connectionString = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(connectionString))
        {
            con.Open();

            bool exists = false;

            // create a command to check if the username exists
            using (SqlCommand cmd = new SqlCommand("select count(*) from Member where UserName = @UserName", con))
            {
                cmd.Parameters.AddWithValue("UserName", UNameTxtBox.Text);
                exists = (int)cmd.ExecuteScalar() > 0;
            }

            // if exists, show a message error
            if (exists)
                ExistLabel.Text = "UserName exists";

My class file code:

public static string searchusername(string username)
{
    connectionString = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
    SqlConnection conn = new SqlConnection(connectionString);
    {
        conn.Open();

        bool exists = false;

        using (SqlCommand comm = new SqlCommand("select count(*) from Member where UserName = @UserName", conn))
        {
            comm.Parameters.AddWithValue("@username", username);
            exists = (int)comm.ExecuteScalar() > 0;
        }
        if (exists)
        {
            return "exist";
        }
        return null;
    }

And the code in my aspx cs file:

 MemberDB.searchusername(UNameTxtBox.Text);

Answers:

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Method 1

Add a label in your page and set the Text property of label to the value returned by the method.

<asp:Label runat="server" ID="userExists"></asp:Label>

And than in code behind do like this

userExists.Text = MemberDB.searchusername(UNameTxtBox.Text);

Method 2

public static bool searchusername(string username)
{
    connectionString = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
    using(SqlConnection conn = new SqlConnection(connectionString))
    {
        conn.Open();

        bool exists = false;

        using (SqlCommand comm = new SqlCommand("select count(*) from Member where UserName = @UserName", conn))
        {
            comm.Parameters.AddWithValue("@username", username);
            exists = (int)comm.ExecuteScalar() > 0;
        }
        return exists;
    }

In your page

if(MemberDB.searchusername(UNameTxtBox.Text))
{
    ExistLabel.Text = "UserName exists";
}

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0