The following (C#) code snippet sets the text property of a label to null,
then tests it for null, only to find out that is isn't. Can anyone explain
why?
Label1.Text = null;
if (Label1.Text == null) {
Label2.Text = "Is null";
} else {
Label2.Text = "Is not null";
}
4  2000 
The short answer is - if you check in your debugger - when you set it to
null it is actually set to "".
"Mike" <Mi**@discussio ns.microsoft.co m> wrote in message
news:E3******** *************** ***********@mic rosoft.com... The following (C#) code snippet sets the text property of a label to null,
then tests it for null, only to find out that is isn't. Can anyone
explain
why?
Label1.Text = null;
if (Label1.Text == null) {
Label2.Text = "Is null";
} else {
Label2.Text = "Is not null";
}
Well I noticed that it is set to "". However, it works fine if you use a
string variable. I realize that there is a difference between a string
property, such as Text and a string variable, it just seems to me they should
behave more similarly.
--Mike
"Jediah L." wrote: The short answer is - if you check in your debugger - when you set it to
null it is actually set to "".
"Mike" <Mi**@discussio ns.microsoft.co m> wrote in message
news:E3******** *************** ***********@mic rosoft.com... The following (C#) code snippet sets the text property of a label to null,
then tests it for null, only to find out that is isn't. Can anyone
explain
why?
Label1.Text = null;
if (Label1.Text == null) {
Label2.Text = "Is null";
} else {
Label2.Text = "Is not null";
}
some properties have code under them... apparently, in this case, if you
attempt to set the Text property to a null, the code forces the value to
String.Empty.
It makes sense. The Text property of a control can't really be null. Null
is not a value. It means that "no value is known". Since the control has
to render the value, it makes sense that it would require you to provide
one.
Be happy you didn't get a runtime error.
--- Nick
"Mike" <Mi**@discussio ns.microsoft.co m> wrote in message
news:F1******** *************** ***********@mic rosoft.com... Well I noticed that it is set to "". However, it works fine if you use a
string variable. I realize that there is a difference between a string
property, such as Text and a string variable, it just seems to me they
should behave more similarly.
--Mike
"Jediah L." wrote:
The short answer is - if you check in your debugger - when you set it to
null it is actually set to "".
"Mike" <Mi**@discussio ns.microsoft.co m> wrote in message
news:E3******** *************** ***********@mic rosoft.com... The following (C#) code snippet sets the text property of a label to
null, then tests it for null, only to find out that is isn't. Can anyone
explain
why?
Label1.Text = null;
if (Label1.Text == null) {
Label2.Text = "Is null";
} else {
Label2.Text = "Is not null";
}
Yup, I guess there must be code back there that makes sure Text is never
null. Thanks for your comments.
"Nick Malik" <ni*******@hotm ail.nospam.com> wrote in message
news:g0AYc.3331 88$a24.112462@a ttbi_s03... some properties have code under them... apparently, in this case, if you
attempt to set the Text property to a null, the code forces the value to
String.Empty.
It makes sense. The Text property of a control can't really be null.
Null is not a value. It means that "no value is known". Since the control has
to render the value, it makes sense that it would require you to provide
one.
Be happy you didn't get a runtime error.
--- Nick
"Mike" <Mi**@discussio ns.microsoft.co m> wrote in message
news:F1******** *************** ***********@mic rosoft.com... Well I noticed that it is set to "". However, it works fine if you use
a string variable. I realize that there is a difference between a string
property, such as Text and a string variable, it just seems to me they
should behave more similarly.
--Mike
"Jediah L." wrote:
The short answer is - if you check in your debugger - when you set it
to null it is actually set to "".
"Mike" <Mi**@discussio ns.microsoft.co m> wrote in message
news:E3******** *************** ***********@mic rosoft.com...
> The following (C#) code snippet sets the text property of a label to
null, > then tests it for null, only to find out that is isn't. Can anyone
> explain
> why?
>
> Label1.Text = null;
> if (Label1.Text == null) {
> Label2.Text = "Is null";
> } else {
> Label2.Text = "Is not null";
> }
>
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