CODEWITHSUNDEEP
vbatextbox
Batu
Batu

Reputation: 11

How to check if textbox.value is numerical?

I am working on a project to create GUI for instrument control.

I created a userform with a couple of textboxes to adjust instrument settings.
Entries to these textboxes should be numerical.

Since textbox.value is stored as variant, I have written a sub to check if the entry is numerical.

Below is the sub I have written and how I call it in textbox change event.

Private Sub cast_Val(user_in As String, user_out As Double) 'Cast User Input'
    If IsNumeric(user_in) = False Then
        user_in = ""
        MsgBox ("Not Numeric")
    Else
        user_out = CDbl(user_in)
    End If
End Sub

Private Sub dwell_txt_AfterUpdate()
    Call cast_Val(cont_ui.dwell_txt.Value, pulse_wid)

    'Dim in_txt As String
    'in_txt = cont_ui.dwell_txt.Value
    'Call cast_Val(in_txt, pulse_wid)
    'cont_ui.dwell_txt.Value = in_txt
End Sub

In debugging mode I checked which step values of user_in, user_out, dwell_txt.Value and pulse_wid change.

I was suspicious of the scope of my variables. Even though all of my code is written under userform scope and dwell_txt (my textbox's name) should be contained underneath it as well, I tried declaring all my procedures and variables as Public. This did not work as well.

I tried changing the value of dwell_txt inside the cast_Val procedure. With this method, I managed to clear, however this is not a reliable method since I have a couple other textboxes in my GUI that I have to use cast_Val procedure in a similar vein.

I tried declaring the parameters of cast_Val procedure as byVal and byRef. In both options, the value inside dwell_txt did not change.

Lastly, I assigned my dwell_txt.Value into a procedure level variable and fed that variable into cast_Val.
This method seems to be a good workaround. I included this method at the end of my change event code. See the commented section for reference.

I am still curious about why my first method did not work. Why can't I feed textbox.value inside a procedure like I have done with a regular variable?

Also on a somewhat unrelated topic, is there a way to change textbox input type to integer/double rather than a variant?

Upvotes: 0

Views: 1571

Answers (1)

Batu
Batu

Reputation: 11

Thanks to all the support of Tim Williams, I have managed to fix the problem. The issue lied on my declaration of the user_in parameter.

Earlier on I have tried String, Int, Double and Variant types. However, this resulted in program passing a copy of the textbox property and did not let me change the property itself inside the procedure. When I declared user_in as Object type and passed cont_ui.dwell_txt, I was able to change the cont_ui.dwell_txt.Value

Below is the working version of the code posted in the original entry.

Private Sub cast_Val(user_in As Object, user_out As Double) 'Cast User Input'
    If IsNumeric(user_in.Value) = False Then
        user_in.Value = CStr(user_out)
        MsgBox ("Not Numeric")
    Else
        user_out = CDbl(user_in.Value)
    End If
End Sub

Private Sub dwell_txt_AfterUpdate()
    Call cast_Val(cont_ui.dwell_txt, pulse_wid)
End Sub

Once again, thanks to Tim Williams for all the help.

Upvotes: 1

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