SQL : getting Comma Separating the values in single field from table

tbl_test

ColA ColB
1        x
2        y
3        z
4        m
5        n


DECLARE @STR VARCHAR(1000)
SELECT @STR = (CASE WHEN @STR IS NULL THEN ColB ELSE @STR + ', ' + ColB END)
FROM tbl_test

SELECT @STR AS ColB


ColB
x, y, z, m, n

Adding new user in DNN

public int createuser()
{
try
{
UserController _UController = new UserController();
UserInfo objUserInfo = new UserInfo();

DotNetNuke.Security.Membership.UserCreateStatus ucs = new DotNetNuke.Security.Membership.UserCreateStatus();
DotNetNuke.Entities.Portals.PortalSettings myPortalSettings = new DotNetNuke.Entities.Portals.PortalSettings();

objUserInfo.FirstName = txtFirstName.Text;
objUserInfo.LastName = txtLastName.Text;
objUserInfo.Username = txtUserName.Text;
objUserInfo.DisplayName = txtFirstName.Text + " " + txtLastName.Text;
objUserInfo.Email = txtEmail.Text;

objUserInfo.PortalID = myPortalSettings.PortalId;
objUserInfo.IsSuperUser = false;
objUserInfo.Membership.CreatedDate = DateTime.Now;
objUserInfo.Membership.Password = this.txtPassword.Text;
objUserInfo.Membership.UpdatePassword = false;
objUserInfo.Roles = new string[] { "Registered Uesrs" };
objUserInfo.Membership.Approved = true;
ucs = DotNetNuke.Entities.Users.UserController.CreateUser(ref objUserInfo);

return objUserInfo.UserID;
}
catch (Exception ex)
{
return 0;
}
}

Highlighting Rows in a GridView

protected void GridView1_RowDataBound ( object sender, GridViewRowEventArgs e )
{
if ( e.Row.RowType == DataControlRowType.DataRow )
{
e.Row.Attributes.Add ( "onmouseover", "this.savedColor=this.style.backgroundColor;this.style.backgroundColor='Yellow'" );
e.Row.Attributes.Add ( "onmouseout", "this.style.backgroundColor=this.savedColor;" );
}
}