TextBox output please ?

Question

Hi friends

Well i do believe that string , object are reference types :) so there default values when not initialized should be NULL right ??

Humm now the problem ..

I have a textbox where when applied the text property on it te output should be in STRING FORMAT am i right here ??

Well now i applied like this

int a = Convert.toInt32(TextBox1.text);

messagebox.show(a);

But i am getting exception : Input string was not in a correct format.

I given no input to textbox i.e i hoped it will take NULL by default but its not happening .. instead its taking this "" .. Y Y Y .

I hope i am clear with my doubt ??

Ty for help

Have a nice day

Vulpes · Answer

Well Text is a string property of the TextBox class. Somewhere within that class there will be a backing field (let's call it _text) which the property gets and sets. Although the default value of that field will be null it is being set to  instead either within its declaration: private string _text = ; or within the TextBox constructor. The default value of the comboBox.Text property is also an empty string. Incidentally you can always check what the default values are by executing a lline like this when the textbox or combobox input area is empty: MessageBox.Show((comboBox.Text == ).ToString()); Even though the default values are an empty string there's nothing to stop you explicitly setting them to null if you want to for some reason. This compiles and runs fine: textBox1.Text = null; However internally I suspect that it will be set back to  if you do this.

SUNIL GUTTA · Answer

Yes yes :) vulpes & stanly .. you are right .. Is my assumption wrong ? i.e text.text which gives us empty string i.e  by default ? but why is it so ?? being a reference type why it is giving me  not NULL ? Y Y But in case of comboBox i.e it does give Null when nothing entered which is OBJECT (return type) which in turn a reference type its sucessfully initialised to ZERO . . ?? ?? /?

Joxin Stanly · Answer

hi it is because the default of TextBox.Text is an empty string () not NULL.

Vulpes · Answer

A TextBox's Text property does in fact have a default value of an empty string  rather than null. However you can deal with this possibility with the following code: int a; int.TryParse(TextBox1.Text out a); If the TextBox is empty or contains something which isn't an integer a will be now be set to zero.

SUNIL GUTTA · Answer

ha haa yes :0 when we give right input there is no problem at all .. I just want to know what happens internally when we give nothing to textbox i.e its taking  instead of NULL yy .. a big yyy

Joxin Stanly · Answer

HI as per your code int a = Convert.toInt32(TextBox1.text); Textbox1 should have a value that can be converted to an integer. and then you have to try below-: Messagebox.show(a .ToString() );