BC42322将'String'转换为'IFormatProvider'时可能会发生VB.NET运行时错误

Question

I'm trying to migrate old VB6(Visual Basic 6.0) Project to VB.net framework 4.6x. But I had to move to .net framework 2.0 first.

I used to convert numbers in TextBox to formatted numbers using ToString as below. In Visual Studio 2017 .net framework 2.0, I have BC42322 warning. Is there a way to solve this?

txtDividend.Text = txtDividend.Text.ToString("###,###,##0")

I also have

On Error GoTo Error_Handle

at the start of the function to handle characters in that textbox

Answer 1

The Text property is already a string, and the ToString() method for string doesn't have the overload you want.

Since it seems this same text field can hold both the formatted and unformatted version of a value, what you may want to do is first strip off any formatting, convert to a numeric type like Integer or Decimal , and then use the ToString() method from there:

Public Function FormatDividend(dividend As String) As String
    Dim extraCharacters As New Regex("[^\d,.-]")
    dividend = extraCharacters.Replace(dividend, "")
    Return FormatDividend(CDec(dividend))
End Function
Public Function FormatDividend(dividend As Decimal) As String
    Return Dividend.ToString("###,###,##0")
End Function

You can call those functions like this:

txtDividend.Text = FormatDividend(txtDividend.Text)

And of course you can tweak that expression however you want, or change the overload and cast to use Integer instead of Decimal.

Answer 2

Since you are trying to migrate from an environment where "1000".ToString("###,##0") produced 1,000, you will want that to work in your new (.net). That solution is to create an extension method that essentially provides the overload.

<Extension>
Function ToString(input as String, format as String) as String
    Static numericOnly As Regex = New Regex("[^\d.-]")
    Dim asDec as Decimal
    Decimal.TryParse(numericOnly.Replace(input, ""), asDec)
    Return asDec.ToString(format)
End Function

Answer 3

Since I have more than one TextBox to use format, I upgraded Joel Coehoorn 's answer to use format TextBox in my project.

First, I created CommonFunction.vb module file

Imports System.Text.RegularExpressions
Module CommonFunction
    Public Function FormatNumberInText(text As String, format As String) As String
        Dim extraCharacters As New Regex("[^\d,.-]")
        text = extraCharacters.Replace(text, "")
        Return FormatNumberInText(CDec(text), format)
    End Function
    Public Function FormatNumberInText(text As Decimal, format As String) As String
        Return text.ToString(format)
    End Function
End Module

and in my TextBox vb file, I used it as below.

txtDividend.Text = FormatNumberInText(txtDividend.Text, "###,###,##0")
txtDividendRatio.Text = FormatNumberInText(txtDividendRatio.Text, "###,###,##0.0#")

Thank you Joel Coehoorn .