To resolve NullReferenceException was unhandled

Question

0.00/5 (No votes)

See more:

Hi All,

I am getting NullReferenceException on the below code snippet,

MyFile.xaml.cs

....

<combobox grid.column="1" name="myCombobox" selectedindex="0" horizontalalignment="Right" verticalalignment="left">
</combobox>

.....

C#

MyFile.cs

private void MyFunction(object sender, RoutedEventArgs e)
{
  string firstval = "";
  if(MyCheckbox.IsChecked == false)
  {
   ....
  }
  firstval = myCombobox.Text.ToString(); //here NullReferenceException occurs 
  else
  firstval = myCombobox.Text.Substring(5);
}

.....

Any Help in resolving the above would be much appreciable.
I am using VS2008 IDE, Win 7 SP1 o/s.

With Regards,
Samanth_90

Posted 11-Apr-12 2:38am

Member 7985084

Updated 11-Apr-12 2:41am

Lakamraju Raghuram

v2

Add a Solution

Comments

[no name] 11-Apr-12 9:02am

Why are you calling ToString on a string? That makes no sense.
What on that line is null?

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Clifford Nelson · Answer 1 · 2012-04-11T10:41:00

Solution 3

Note that

firstval = myCombobox.Text.Substring(5);

will throw an exception if the length of the text in the text box is less than 5. Also the others are right in that you do not need a ToString() with Text property from a text box

Posted 11-Apr-12 10:41am

Clifford Nelson

Saurabh_Damle · Answer 2 · 2012-04-11T03:05:00

Solution 2

First check whether myCombobox.Text is null or not.
Secondly, you don't have to do myCombobox.Text.ToString(), myCombobox.Text returns string itself.

Posted 11-Apr-12 3:05am

Saurabh_Damle

Lakamraju Raghuram · Answer 3 · 2012-04-11T02:43:00

Solution 1

I guess

myCombobox.Text

is null value.
Can you confirm that for me?

Posted 11-Apr-12 2:43am

Lakamraju Raghuram