Question

I have a code looks like the following.

I get message from query string. After that I’m going to get it that to message array(msg_arr).But all of these things in inside the Page_load.

But why does this error show?

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        try
        {
            string messageIn = Request.QueryString["msg"];  
            // some code here
        }
        catch(Exception ex)
        {
            Response.Write(ex.Message);
        }

        string[] msg_arr = messageIn.Split(' '); // error shown here
        int size = msg_arr.Length;

        if(!CheckUserExistAndReporter("messageIn"))
        {
           // Response.Redirect("~/test.aspx");
        }
        else
        {

Answer 1

You are declaring the messageIn variable inside the try{} block and hence its scope is only within the try{} block.

You should do something like this

protected void Page_Load(object sender, EventArgs e)
{
string messageIn=string.Empty;
    if (!IsPostBack)
    {
        try
        {

             messageIn = Request.QueryString["msg"];

            // some code here


        }
        catch(Exception ex)
        {
            Response.Write(ex.Message);
        }


        string[] msg_arr = messageIn.Split(' '); // error shown here
        int size = msg_arr.Length;

        if(!CheckUserExistAndReporter("messageIn"))
        {
           // Response.Redirect("~/test.aspx");
        }