C# Compiling error in newer version Visual Studio

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Hello,

I'm compiling a program which was originally build in Visual C# 2005. I'am using visual C# 2010. And I keep getting "NullReference Execption was unhandled" errors on the following function:
the error occurs on the line with DataBuffer. DataBuffer is just an private string set to

C#

null

on initialisation.

C#

if (DataBuffer.Contains(ok))
{
    okFound = true;
}

and

C#

string temp = getLine(DataBuffer.Substring(mylocation));
if (!checkTypeFound())
{
    if (temp != null)
    {
        parseDeviceType(temp);
    }
    checkTypeFound();
}

DataBuffer information is loaded in this function:

C#

private void ser1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    while (ser1.BytesToRead > 0)
    {
        string data = ser1.ReadExisting();
        DataBuffer += data;
    }
}

The serial port is opened somewhere else in the code. There have been no changes to the code only the compiler is different. What line should I add, and where to solve this error?

Posted 3-Sep-12 21:24pm

pieterjann

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2 solutions

Solution 2

All 3 of the references to DataBuffer you have shown will cause the NullReferenceException to be thrown if DataBuffer is null.
Why not just initialize it to string.Empty instead of null ?

Posted 4-Sep-12 9:44am

Matt T Heffron

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Ganesh Nikam · Accepted Answer · 2012-09-03T22:32:00

Solution 1

hiii,

add Condition

if(!string.isNullOrEmpty(DataBuffer))
{
if(DataBuffer.Contains(ok))
{
okFound = true;
}
}

Posted 3-Sep-12 22:32pm

Ganesh Nikam

Comments

pieterjann 4-Sep-12 4:58am

This does not solve the problem, but only removes the error. I must have the problem that results to the error solved. Thanks anyway!