Ive got a Form application in VB.NET.
I have many text boxes on one form (about 20). Is there anyway to check them all at once to see if they are empty instead of writing out a massive line of code to check each one individually such as
If txt1.text = "" Or txt2.text="" Then
msgbox("Please fill in all boxes")
That just seems like a long way around it?
You could also use LINQ:
Dim empty =
Me.Controls.OfType(Of TextBox)().Where(Function(txt) txt.Text.Length = 0)
If empty.Any Then
MessageBox.Show(String.Format("Please fill following textboxes: {0}",
String.Join(",", empty.Select(Function(txt) txt.Name))))
End If
The interesting method is Enumerable.OfType
The same in query syntax(more readable in VB.NET):
Dim emptyTextBoxes =
From txt In Me.Controls.OfType(Of TextBox)()
Where txt.Text.Length = 0
Select txt.Name
If emptyTextBoxes.Any Then
MessageBox.Show(String.Format("Please fill following textboxes: {0}",
String.Join(",", emptyTextBoxes)))
End If
I would recommend using the Validating event of the TextBox controls, with an error provider control (just add one to your form):
Private Sub TextBox_Validating( sender As System.Object, e As System.ComponentModel.CancelEventArgs) Handles TextBox1.Validating, TextBox2.Validating, ComboBox1.Validating
Dim ctl As Control = CType(sender, Control)
If ctl.Text = ""
e.Cancel = True
ErrorProvider1.SetError(ctl,"Please enter a value")
End If
End Sub
Then you can just call:
ErrorProvider1.Clear()
If Me.ValidateChildren()
' continue on
End If
The nice thing about this is that the user is informed about which textbox is missing and required. This works with other controls besides textboxes, so you can provide a more complete solution. Also, if you get to a later point where one or two textboxes don't need to have values, you simply do not validate them instead of having to add special cases in your loops.
Finally, if you don't want to type out all of the controls, then you could do this in form load:
For Each c As Control In Me.Controls
If TypeOf(c) is TextBox or TypeOf(c) is ComboBox
AddHandler c.Validating, AddressOf Me.TextBox_Validating
End If
Next
A very simplistic approach would be to gather all the TextBox controls in a sequence using the Enumerable.OfType LINQ method and then iterate through it in a For Each loop:
Dim textBoxes = Me.Controls.OfType(Of TextBox);
For Each t In textBoxes
If String.IsNullOrEmpty(t.Text) Then
MsgBox("...")
Exit For
End If
Next t
If TextBox field is empty then the message box will appear saying "Complete Entry!".
Dim t
For Each t In Me.Controls
If TypeOf t Is TextBox Then
If t.Text = "" Then
MsgBox("Complete Entry!")
Exit Sub
Exit For
End If
End If
Next
Sub for check Empty Textbox in GroupBox, you can use this:
Public Sub CheckEmptyTextbox(Byval groupbox as GroupBox)
Dim txt as control
For Each txt in groupbox.Controls
IF TypeOF txt is Textbox then
IF txt.Text="" Then
MsgBox("Please Input data to textbox.")
Exit For
End IF
End IF
Loop
End Sub
I found this, perhaps you can modify it to check if all textboxes are clear rather than what it currently does which is just clear all textboxes
Public Sub ClearTextBox(ByVal root As Control)
For Each ctrl As Control In root.Controls
ClearTextBox(ctrl)
If TypeOf ctrl Is TextBox Then
CType(ctrl, TextBox).Text = String.Empty
End If
Next ctrl
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
ClearTextBox(Me)
End Sub
Public Class freestyle
Private Sub TextBox3_TextChanged(sender As Object, e As EventArgs) Handles TextBox3.TextChanged
If Trim(TextBox3.Text) = "" And Me.Visible Then
MsgBox("fill in the textbox")
TextBox3.BackColor = Color.Yellow
Else
' MsgBox("great one !!!")
End If
End Sub
Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
If Trim(TextBox2.Text) = "" And Me.Visible Then
MsgBox("fill in the textbox")
TextBox2.BackColor = Color.Yellow
Else
'MsgBox("great one !!!")
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If Trim(TextBox1.Text) = "" Or Trim(TextBox2.Text) = "" Or Trim(TextBox3.Text) = "" And Me.Visible Then
MsgBox("Please fill the necesary", MsgBoxStyle.Critical, "Error")
TextBox1.Focus()
Else
MsgBox("Nice Work !!!")
End If
End Sub
Private Sub TextBox1_Leave(sender As Object, e As EventArgs) Handles TextBox1.Leave
If Trim(TextBox1.Text) = "" And Me.Visible Then
MsgBox("fill in the textbox")
TextBox1.BackColor = Color.Yellow
Else
' MsgBox("great one !!!")
End If
End Sub
End Class
