Question

I am just learning how to use classes in my projects. I have been working on a DataAccessClass.cs and am doing well (I think).
Taking a break from data access, I decided to try to make a void into a class. This void sends a message to the client as a javascript alert. It works well, but has to be included on each page. When I tried to make it a class, I was informed that my class does not contain a definition for ClientScript. I included all the “using” directives from the original page to no avail… Any hints or suggestions would be greatly appreciated.

The original code:

//------------------------------------------------------------------------------
//Name: SendErrorMessageToClient
//Abstract: show alert on client side
//------------------------------------------------------------------------------

protected void SendErrorMessageToClient(string strErrorType, string strErrorMessage)
{
    string strMessageToClient = "";

    //Allow single quotes on client-side in JavaScript
    strErrorMessage = strErrorMessage.Replace("'", "\\'");

    strMessageToClient = "<script type=\"text/javascript\" language=\"javascript\">alert( '" + strErrorType + "\\n\\n" + strErrorMessage + "' );</script>";

    this.ClientScript.RegisterStartupScript(this.GetType(), "ErrorMessage", strMessageToClient);

}

Messages are sent into this void like this:

if (DataAccessClass.OpenSqlConnection(ref Conn, strConn, out strErrorMessage) == false)
        {
            string strErrorType = "Database Connection Error:";
            SendErrorMessageToClient(strErrorType, strErrorMessage);
        }

Or this:

catch (Exception excError)
    {
        string strErrorType = "Unhandled Exception:";
        string strErrorMessage = excError.Message;
        SendErrorMessageToClient(strErrorType, strErrorMessage);
    }

Answer 1

You are receiving the error as ‘Clientscript’ is a property derived from a System.Web.UI.Page and by moving into a separate class file, you no longer have access to this property.

You could solve this by passing in the page as well, and amending the code to

protected void SendErrorMessageToClient(string strErrorType, string strErrorMessage, Page page)
{
    string strMessageToClient = "";

    //Allow single quotes on client-side in JavaScript
    strErrorMessage = strErrorMessage.Replace("'", "\\'");

    strMessageToClient = "<script type=\"text/javascript\" language=\"javascript\">alert( '" + strErrorType + "\\n\\n" + strErrorMessage + "' );</script>";

    page.ClientScript.RegisterStartupScript(this.GetType(), "ErrorMessage", strMessageToClient);

}