Check all yellow checkboxes

[David Callen]

Hey Guys

Quick question which I'm sure is actually pretty simple but I'm pretty new to this.

I have a piece of code for a program where when a specific checkbox is checked\unchecked (In this case "Allyellow") it checks\unchecks any checkboxes within a group of 14 with a lightyellow backcolor.

While the piece of code below does this fine it seems to me to be very clunky and it must be possible to streamline it.

Any help would be much appriciated
Thanks
Dave

Private Sub Allyellow_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Allyellow.CheckedChanged
 
        If Allyellow.Checked = True Then
            If CheckBox1.BackColor = Color.LightYellow Then
                CheckBox1.Checked = True
            End If
            If CheckBox2.BackColor = Color.LightYellow Then
                CheckBox2.Checked = True
            End If
            If CheckBox3.BackColor = Color.LightYellow Then
                CheckBox3.Checked = True
            End If
            If CheckBox4.BackColor = Color.LightYellow Then
                CheckBox4.Checked = True
            End If
            If CheckBox5.BackColor = Color.LightYellow Then
                CheckBox5.Checked = True
            End If
            If CheckBox6.BackColor = Color.LightYellow Then
                CheckBox6.Checked = True
            End If
            If CheckBox7.BackColor = Color.LightYellow Then
                CheckBox7.Checked = True
            End If
            If CheckBox8.BackColor = Color.LightYellow Then
                CheckBox8.Checked = True
            End If
            If CheckBox9.BackColor = Color.LightYellow Then
                CheckBox9.Checked = True
            End If
            If CheckBox10.BackColor = Color.LightYellow Then
                CheckBox10.Checked = True
            End If
            If CheckBox11.BackColor = Color.LightYellow Then
                CheckBox11.Checked = True
            End If
            If CheckBox12.BackColor = Color.LightYellow Then
                CheckBox12.Checked = True
            End If
            If CheckBox13.BackColor = Color.LightYellow Then
                CheckBox13.Checked = True
            End If
            If CheckBox14.BackColor = Color.LightYellow Then
                CheckBox14.Checked = True
            End If
        ElseIf Allyellow.Checked = False Then
            If CheckBox1.BackColor = Color.LightYellow Then
                CheckBox1.Checked = False
            End If
            If CheckBox2.BackColor = Color.LightYellow Then
                CheckBox2.Checked = False
            End If
            If CheckBox3.BackColor = Color.LightYellow Then
                CheckBox3.Checked = False
            End If
            If CheckBox4.BackColor = Color.LightYellow Then
                CheckBox4.Checked = False
            End If
            If CheckBox5.BackColor = Color.LightYellow Then
                CheckBox5.Checked = False
            End If
            If CheckBox6.BackColor = Color.LightYellow Then
                CheckBox6.Checked = False
            End If
            If CheckBox7.BackColor = Color.LightYellow Then
                CheckBox7.Checked = False
            End If
            If CheckBox8.BackColor = Color.LightYellow Then
                CheckBox8.Checked = False
            End If
            If CheckBox9.BackColor = Color.LightYellow Then
                CheckBox9.Checked = False
            End If
            If CheckBox10.BackColor = Color.LightYellow Then
                CheckBox10.Checked = False
            End If
            If CheckBox11.BackColor = Color.LightYellow Then
                CheckBox11.Checked = False
            End If
            If CheckBox12.BackColor = Color.LightYellow Then
                CheckBox12.Checked = False
            End If
            If CheckBox13.BackColor = Color.LightYellow Then
                CheckBox13.Checked = False
            End If
            If CheckBox14.BackColor = Color.LightYellow Then
                CheckBox14.Checked = False
            End If
        End If
    End Sub

[rythmic]

How about putting all checkboxes in an array and then iterate through that array.

I actually don't know VB syntax at all but i do know C# and that approach would work fine.

Since I don't know VB syntax I can't help you there but a conceptual solution would be this:

Dim cbs As CheckBox[] = {All checkboxes here}
Dim allYellowStatus As bool = Allyellow.Checked; 
For Each checkBox As CheckBox In cbs {
    If checkBox.BackColor = Color.LightYellow Then
        checkBox.Checked = allYellowStatus
    End If
}
 

Something like that seems a bit easier to grasp.

[Joseph Martell]

There is actually a better way to do this. Your controls on your form are already in a collection. What you need is an efficient way to get all check boxes that have the light yellow background.

IF you are using .Net framework 3.5 or greater then you have access to a couple of extension methods that can make life a little easier for you.

Here is a complete code sample that should work:

Dim lightYellowCheckBoxes As List(Of CheckBox) = Nothing
 
lightYellowCheckBoxes = Me.Controls.OfType(Of CheckBox).Where(Function(chkBox As CheckBox) chkBox.BackColor = Color.LightYellow)
 
If (AllYellow.Checked) Then
 
    For Each chkBox In lightYellowCheckBoxes
        chkBox.Checked = True
    Next
Else
    For Each chkBox In lightYellowCheckBoxes
        chkBox.Checked = False
    Next
End If
 

The key to this code is the following line:

lightYellowCheckBoxes = Me.Controls.OfType(Of CheckBox).Where(Function(chkBox As CheckBox) chkBox.BackColor = Color.LightYellow)

This is kind of complicated, especially if you've never seen it before (and the VB syntax makes this a little bit less clear, in my opinion). Lets break it down:

lightYellowCheckBoxes is a list(of CheckBox) so it holds a collection of checkboxes. Because of the way that this is implemented it dynamically sizes itself to hold as many check boxes as you need. This means you don't have to worry about sizing your array correctly, or manually resizing your array during processing.

Me.Controls references the collection of controls that are currently on the window. The .Net framework 3.5 introduces the extension method OfType:

Me.Controls.OfType(Of CheckBox)

This statement returns a collection of all the check box controls in the Me.Controls collection.

Finally, the .Where extension method is also introduced in .Net framework 3.5. So, with Me.Controls.OfType(Of CheckBox) we accessed a collection of check boxes on the form. Using the .Where extension allows to return another collection of controls. Unlike .OfType, which just filters on the type of the control, we get to supply a predicate of the .Where extension ourselves.

From the statement:

lightYellowCheckBoxes = Me.Controls.OfType(Of CheckBox).Where(Function(chkBox As CheckBox) chkBox.BackColor = Color.LightYellow)
 

the predicate is provided by this part of the code:

Function(chkBox As CheckBox) chkBox.BackColor = Color.LightYellow
 

This statement creates a Lambda function. Think of a Lambda function as a single-purpose, unnamed function that we create on-the-fly and use for a very specific reason. In this case, I am creating a function that takes a check box and returns a boolean value based on whether the background of that check box was Color.LightYellow. The return type is implied.


Now lightYellowCheckBoxes references a list of checkboxes on the current form with a background of light yellow.

This code can be made more efficient if the check boxes with light yellow backgrounds do not change. You could make lightYellowCheckBoxes a private class member (instead of a local collection in the function) and put:

lightYellowCheckBoxes = Me.Controls.OfType(Of CheckBox).Where(Function(chkBox As CheckBox) chkBox.BackColor = Color.LightYellow)
 

in your form load event. That way you are only creating your list of check boxes once.

The if statements and loops are pretty self explanatory. I chose to nest the for loops inside the if statements because that way your code would perform one conditional test and then fall into a loop. Nesting the if statement inside the loop would mean that the conditional test occurs in each iteration of the loop. Just a side note.

You should also know that everything that was achieved with the .OfType and .Where extension methods can be achieved with other code as well. .OfType and .Where are just meant to be syntactic sugar to make life easier for you.