Question

hello i had this code and it worked well:

    private void Textparsing()
    {               
        using (StreamReader sr = new StreamReader(Masterbuildpropertiespath))                 
        {                    
                while (sr.Peek() >= 0)
                {
                    if (sr.ReadLine().StartsWith("Exec_mail"))
                    {
                        ExecmailCheckBox.IsChecked = true;
                    }
                    if (sr.ReadLine().StartsWith("Exec_text"))
                    {
                        ExectextCheckBox.IsChecked = true;
                    }
                    if (sr.ReadLine().StartsWith("Exec_3"))
                    {
                        Exec3CheckBox.IsChecked = true;
                    }
                    if (sr.ReadLine().StartsWith("Exec_4"))
                    {
                        Exec4CheckBox.IsChecked = true;
                    }
                }              
        }               
    }

It was perfect and i got all the 4 checkbox checked when i got the correct text in the file.

However, I am receiving Nullreference error over at this line:

if (sr.ReadLine().StartsWith("Exec_text"))
{
      ExectextCheckBox.IsChecked = true;
}

When test it out for 1 target(means i make the other 3 targets as comments), it all worked fine. Please advice

Answer 1

With the evaluation of EACH if statement a line is being read. Better is to read the line and then have the multiple ifs:

var line = reader.ReadLine();
if(!String.IsNullOrEmpty(line)
{
    if(line.StartsWith(...))
    { ... }
    if(line.StartsWith(...))
    { ... }
}