IF condition as presence check?

[ppatryk]

Hi, is it ok to use an if condition as a presence check, this is my code -

if (textBox1 != null)
{
MessageBox.Show("Dont Leave Blank");

}

else

MessageBox.Show("Successfully added");

my code runs however no matter if there is text in textbox1 or if its left empty it shows "Dont Leave Blank" any suggestions?

thanks

[Mitja Bonca]

Wrong. You have to put a property of a textbox control on the end of it to check it:

if(textBox.Text != String.Empty)
{
   //not empty (not null, even empty and null are not the same things)
}
else
{
   //empty!
}

[ppatryk]

Thats great, thanks for the help.

[Mitja Bonca]

No problem. Just thread as answered (or vote as useful), to close the thread.
bye

[gusano79]

if(textBox.Text != String.Empty)
{
   //not empty (not null, even empty and null are not the same things)
}
else
{
   //empty!
}

See also: <a href="http://msdn.microsoft.com/en-us/library/system.string.isnullorempty.aspx">String.IsNullOrEmpty</a> , <a href="http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx">String.IsNullOrWhiteSpace</a> ; depending on what your needs are.

For example:

if(String.IsNullOrWhiteSpace(textBox1.Text))
{
    ...
}