CODEWITHSUNDEEP
vb.netvisual-studio
Silver616
Silver616

Reputation: 15

Clear all textboxes in vb.net throws an error

I am using the following as a workaround:

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 = 0
            If TypeOf ctrl Is ComboBox Then CType(ctrl, ComboBox).Text = String.Empty

        Next ctrl
End Sub

the reason i am setting the textboxes to 0 is because when I set String.Empty, one text box (containing only Int16) throws a conversion error. anyone help on stopping the error or just ignoring that one textbox?

As per Andrews response, I ran the code again, and i get the following:

+ $exception {"Conversion from string """" to type 'Short' is not valid."} System.InvalidCastException

The code highlighted is:

Dim age As Int16 = Txt_CharAge.Text

Please bear with me a little, I am totally new to this and am completely self taught. If you need further code to help, just let me know. Thanks

Upvotes: 1

Views: 258

Answers (1)

Andrew Morton
Andrew Morton

Reputation: 25066

When you have a line such as

Dim age As Int16 = Txt_CharAge.Text

you are telling the computer to put a string into a number. Without Option Strict On, it is free to make up any way it likes of stuffing a string (which is not an Int16) into an Int16. You have given up your control of what is happening at that point.

The better way is to tell it how to convert the characters of the text into a number. (See The Treachery of Images for an explanation that a representation of some thing is not that thing.)

There is a ready-made set of methods named TryParse for many of the built-in types.

So, instead of

Dim age As Int16 = Txt_CharAge.Text

you should have

Dim age As Integer
Integer.TryParse(Txt_CharAge.Text, age)

The TryParse methods are actually functions which return True if the parse was successful, otherwise they return False (and set the variable to its default value), but in this case it appears that you don't need to know if the parse succeeded because the default value of 0 for an Integer will suffice.

Note that there isn't really a need to use an Int16 instead of an Integer unless you know why you need to add the complication of using an Int16 instead of an Integer.

Upvotes: 2

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