how to validate the Textbox.text is not empty?

[LittleDong]

would somebody show me a convenient way to validate Textbox's value are not null or empty in Winform.
if-else condition is only good for fewer textboxs in a winform or solution,
if(Textbox1.text==null)
{
...
}
else
{
...
}

but if there are lots of textbox?

[mohit2k8]

may this code would help you..
after converting textbox value into string
if(textbox1.text=="")

[LittleDong]

if there are six textforms in a winform
I think it's not a good way to write
if((Textbox1.text=="")&&(Textbox1.text==null))
.
.
if((Textbox2.text=="")&&(Textbox2.text==null))
.
.
if((Textbox3.text=="")&&(Textbox3.text==null))
.
.
if((Textbox4.text=="")&&(Textbox4.text==null))
.
.
.
.

@mohit2k8

[r035198x]

You have many options, IMO, worst is to create a helper method that does this on a list of text components, much better is to learn the decorator pattern:http://en.wikipedia.org/wiki/Decorator_pattern
You decorate the text boxes with ability to validate their text. You are going to need to learn to learn this pattern if you want to write maintainable gui programs anyway.

[rexzel0230]

hello.. you can create a function to check if the textbox is empty.

sample (vb.net)

function txtIsEmpty(frm as form)
    dim isempty as boolean=true
        For Each crl As Control In frm.Controls
            If TypeOf crl Is TextBox Then
                if trim(trl.text)="" then
                    isempty=true
                    exit for
                else
                    isempty=true
                end if
            ElseIf TypeOf crl Is GroupBox Then
                'if the control is groupbox, its contents will not be included.
                For Each crl1 As Control In crl.Controls
                    If crl1.GetType Is GetType(TextBox) Then
                        if trim(crl1.text)="" then
                            isempty=true
                            exit for
                        else
                            isempty=false
                        end if
                    End If
                Next
            End If
        Next
    txtIsEmpty=isempty
end function

the above function will check all of the textbox on your form as well as inside the group box

to call the function:

if txtIsEmpty(Form1) then
msgbox "Other texts are empty."
end if

[PalomoSoft]

for VB6

************
Public function cHecker(frm as form)as Boolean
  dim obj as string
  For each obj in frm
    If typeof obj is textbox then
      If obj.text="" then
         checker=false
         msgbox "Textbox is empty"
         exit function
      End if
    End if
  Next obj
End Function
 
***********syntax
if checker= true then
   msgbox "Textbox is not empty"
end if

[bshelton3]

For simply checking to see if a text string is null or empty I would use this:
http://msdn.microsoft.com/en-us/libr...llorempty.aspx

[bshelton3]

For simply checking to see if a text string is null or empty I would use this:
http://msdn.microsoft.com/en-us/libr...llorempty.aspx

[PsychoCoder]

There's no need to write a method for this, just use String.IsNullOrEmpty like this

if(string.IsNullOrEmpty(TextBox1.text))
{ 
    //do work here
}

You could also use string.IsNullOrWhiteSpace

[r035198x]

Did you mean

if(string.IsNullOrEmpty(Textbox1.text)){

instead?

Mod edit
For line #1 instead of :

if(string.IsNullOrEmpty(TextBox1))

[PsychoCoder]

Yes I did, thanks for seeing that