I am trying to write a function called HasUnsavedChanges which basically should be called when you are closing the form. i.e after saving the item, it should check the values in the controls against the values in Tag property which are in the same function, e.g. txtFirstName.Tag = .ContactFirstname and txtFirstName.Text = .ContactFirstname. If there is any difference between the two, return True. On closing the form, if this function returns true, then ask if changes should be saved.
I think the right way would be to write a For loop to loop through the controls, but I'm stuck after that.
Assuming you have the .Text and .Tag properties stored in the same control, try something like this:
For Each objControl As Control In frmMain.Controls
If TypeOf objControl is TextBox Then
If objControl.Tag <> objControl.Text Then
'---Changes have been made!---
End if
End if
Next
Obviously, you'll need to replace "frmMain" with your form's name.
Related
If I'm viewing a form and I set the enabled property of the control with tab index = 0, does the cursor then move to the next tab index? Do I need to, and is there a way, to force the tab to set to the first control with Enabled = True?
So in order to achieve this (assuming there are no panels on your form), this is how you could iterate through the controls in tab order. The first control which you encounter and which is enabled, you set the focus on it and leave the Sub. The myFirstControl variable is initialized by you with the first control in the tab order list of the form.
Private Sub IterateControls()
Dim ctrl As Control = myFirstControl
While ctrl IsNot Nothing
If ctrl.Enabled = True Then
Me.ActiveControl = ctrl
Exit Sub
End If
ctrl = Me.GetNextControl(ctrl, True)
End While
End Sub
If you have panels also, you should build a dictionary of panels (with the panel as key, its first control as value) and take them one by one using a For loop. The For loop should be placed to include the whole method's code, but this time you initiate the ctrl variable with the first control from the panel (i.e. the value of the current dictionary entry), instead of the first control of the Form, and also you would call myPanel.GetNextControl(...) instead of Me.GetNextControl(...). The other code lines should remain the same. If this is not helpful enough, add a comment and I will edit my answer.
I have a checkbox control that i need to hide if a Boolean value is false. I have tried using the Detail_Format event to no avail. i put the field value into another checkbox, then tried setting the visible property from the value in the checkbox, no dice. In the image below, the rightmost checkbox is showing the value of the field that determines if the checkbox to the left of it should be shown. I have the following code
Private Sub Detail_Format(Cancel As Integer, FormatCount As Integer)
If Me.chkRequireverify = True Then
Me.chkVerified.Visible = True
Else
Me.chkVerified.Visible = False
End If
'Me.chkVerified.Visible = Me.chkRequireverify
End Sub
when i tried using the Detail_Paint event, it errored out telling me that i cant change the visible property in this event.
Your code looks to be correct and could be shortened to simply:
Private Sub Detail_Format(Cancel As Integer, FormatCount As Integer)
Me.chkVerified.Visible = Me.chkRequireverify
End Sub
However, I believe the event handler for the OnFormat event will only be evaluated when viewing the report in Print Preview view, rather than in Report view.
Whilst the OnPaint event fires in Report view, you cannot modify certain properties after the report has been formatted, the Visible property being one such property, along with the Height & Width properties (and so you also cannot shrink the checkboxes to zero size).
It's been a while since I've used Access and VBA, but I believe what you're missing is .Value after the checkbox name in the if clause.
Try this : If Me.chkRequireverify.Value = True
I have groupboxes that contain textboxes and I want to set all of them to ReadOnly=True. Here is what I tried (doesn't work):
EDIT (I forgot about Split container):
For Each SplitCon As Control In Me.Controls
If TypeOf SplitCon Is SplitContainer Then
For Each GBox As Control In SplitCon.Controls
If TypeOf GBox Is GroupBox Then
For Each ctrl As Control In GBox.Controls
If TypeOf (ctrl) Is TextBox Then
CType(ctrl, TextBox).ReadOnly = True
End If
Next
End If
Next
End If
Next
You can simplify things a great deal. Rather than looking thru all sorts of Control collections, create an array to act as a ToDo list. Then you can get rid of all the TypeOf and CType in the loop used.
' the ToDo list
Dim GrpBoxes = New GroupBox() {Groupbox1, Groupbox2,
Groupbox3, Groupbox4}
For Each grp In GrpBoxes
For Each tb As TextBox In grp.Controls.OfType(Of TextBox)()
tb.ReadOnly = True
Next
Next
Your code no longer depends on the form layout of the moment. The only thing you have to remember is to add any new GroupBox items to your list. You can also declare the array once ever for the whole form if you prefer (or even in the For Each statement)
Rather than working with Control objects, Controls.OfType(Of T) filters the collection and returns an object variable of that type, so there is no need to cast it or skip over controls you are not interested in. You can also tack on a Where method to further refine the list to include only do those with a certain name or Tag.
I am creating a form in Access which will be used as an order sheet for classroom materials. I have the available resources listed and a text box next to the resource where the user inputs the quantity they desire.
My VBA code checks to see if any entries have been made by using the following. (I am using Nz() to allow for Null results):
QuantCheck = Nz(Box1.Value, 0) + Nz(Box2.Value, 0) + Nz(Box3.Value, 0)
Where "QuantCheck" is the variable I am using in the IF statement which begins the workflow:
If QuantCheck > 0 Then
I would like to clean this up by using some kind of loop statement, however I am not able to extract the .value from a string. I would love something like the following which I could incorporate into a loop:
"Box"&VariableNumber.Value
From what I can tell, I am not able to use a string (concatenated or otherwise) as the base for the .value call.
It is interesting that there is a way to accomplish this when using a SQL statement. I have this elsewhere in the code which works nicely:
SQLStr = "INSERT INTO OrderRequests VALUES (cbSchool, txtName, Title" & x & ".caption, Box" & x & ")"
Here I have a variable "x" which increases with each loop to change the Title line, and the Box line.
Any help is appreciated.
I suggest you use the Tag property of the controls. Put "QuantCheck" in the Tag property of any control you want to include. Then
Function QuantitiesExist(frm As Form) As Boolean
Dim Ctrl As Control
Const sQUANTCHK As String = "QuantCheck"
For Each Ctrl In frm.Controls
If Ctrl.Tag = sQUANTCHK Then
If Nz(Ctrl.Value) > 0 Then
QuantitiesExist = True
Exit For
End If
End If
Next Ctrl
End Function
Now you get self documenting code
If QuantitiesExist(Me) Then
And when you add/delete/change controls, you don't have to edit your code. Just set up new controls with the proper tags.
You could loop through the control on the for checking the names and then if it is the one you wanted take an action on it, is this what you was thinking of?
Dim Ctrl As Control
For Each Ctrl In Me.Controls
If Ctrl.Name = "TxtPath" Then ' "Box" & VariableNumber Then
MsgBox Ctrl.Value
End If
Next
I'm facing a deadend When trying to call this sub :
Public Sub backblue(ByVal frm As Form, ByVal boxname As String)
For i = 1 To 3
CType(frm.Controls(boxname & i.ToString()), TextBox).BackColor = Color.LightBlue
Next
End Sub
with button click event :
Private Sub Button1_click and bla bla....
backblue(Me, "txb1_")
End Sub
Can anybody show me a suggestion to fix the code.
It throws "Object Referrence not set to an instance bla bla" error
For information the textbox names are :
txb1_1 , txb1_2 , txb1_3
(these are some of the many textboxes in the form that i want its bakcolor changed)
and these three textboxes are already created through designer, not from execution.
i did check the textboxes names and there's nothing wrong.
the form class is also public.
if they are the only textboxs on said form you can just loop through
For Each box as Textbox In frm.Controls
box.BackColor = Color.LightBlue
Next
This error will occur if you do not declare the Form class to be public.
Also, make sure the textbox names are really correct, although this will probably cause a different error.
If you create the textboxes during execution, make sure they are initialized with New and added to the form's Controls collection.
Try this....
Public Sub backblue(ByVal frm As Form, ByVal prefix As String)
For i = 1 To 3
Dim bxName as String = prefix & i.ToString()
Dim bx as TextBox = CType(frm.Controls(bxName), TextBox)
If bx Is Nothing Then
MsgBox("Unable to find text box " +bxName)
Dim mtch() As Control = frm.Controls.Find(bxName, true)
If mtch.Length> 0 then
bx = mtch(0)
Else
Continue For
End if
End If
Bx.BackColor = Color.LightBlue
Next
End Sub
Although, a better solution would be to either create the textboxes inside a control and pass that control to BackBlue or to create an collection that has the controls and pass that in. Which brings up what is most likely yor problem your control is contained in a sub component and thus is not in the main form control collection
Alternative, you could use either the tag of the control or create a component control that implements IExtenderProvider and add it to the form --all of the above would effectively allow you to define the controls and/how they should be handled at designtime.
It may really seem that the names generated by this loop may not be the names of the original textboxes. My suggestion is before setting this Color property verify that the names generated by this loop are indeed the actual names. Maybe output this in a messagebox:
MessageBox.Show(boxname & i.ToString()) for each loop before you set the property