How to get text from Byte Array

[kcvinker]

Hi all,
I am making a class in Boo to automate some tasks. I did it in VB.Net earlier. This is my VB.Net code.
`Public Function EnumWindowProc(ByVal Hwnd As IntPtr, ByVal LParam As IntPtr) As Boolean

    If IsWindowVisible(Hwnd) Then
        Dim Length As Integer = GetWindowTextLength(Hwnd)
        Dim Ret(Length * 2) As Byte
        GetWindowText(Hwnd, Ret, Length + 1)
        Dim Text As String = ""
        For i As Integer = 0 To (Length - 1) * 2
            If Ret(i) <> 0 Then
                Text &= Chr(Ret(i))
            End If
        Next
        If Text <> "" Then    ' if window has a title
            Output.Add(Text)
        Else                    ' if window has no titles
            Output.Add((Hwnd))

        End If


    End If
    Return True

End Function`

And this is my try in Boo.
`private def EnumWindowProc(Hwnd as IntPtr, LParam as IntPtr) as bool:

	if IsWindowVisible(Hwnd):
		Length as int = GetWindowTextLength(Hwnd)
		Ret as (byte) = array(byte, ((Length * 2) + 1))
		GetWindowText(Hwnd, Ret, (Length + 1))
		Text as string = ""
		for i in range(0, (((Length - 1) * 2) + 1)):
			if Ret[i] != 0:
				Text += String.Chr(Ret[i])
		if not string.IsNullOrEmpty(Text):
			// if window has a title
			Output.Add(Text)
		else:
			// if window has no titles
			Output.Add(Hwnd)		
		
	return true		

`
I am having an error in "String.Char(Ret[i]) ". Please help.

[kcvinker]

edited

[masonwheeler]

What error are you encountering? Can you paste it in here?

[masonwheeler]

Looking at this, it appears that you're starting with UTF-16 characters and trying to lower them to ANSI by discarding the 0s. This will break and give you weird mojibake if you have non-ANSI characters in there anywhere. So I'd start by reinterpreting the buffer as an array of 16-bit elements:

	var Ret = array(byte, (Length * 2) + 1)
	var chars = array(UInt16, Length + 1)
	GetWindowText(Hwnd, Ret, Length + 1)
	Buffer.BlockCopy(Ret, 0, chars, 0, Ret.Length)

If you want an equivalent of VB.NET's Chr() function for 16-bit characters, you'd use Microsoft.VisualBasic.Strings.ChrW. Getting a 16-bit 0 here would mean the end of the string, so you could do it like this. First, make sure to import System.Linq.Enumerable at the top of your file. Then:

	Text = string(chars.TakeWhile({c | c > 0}).Select(Microsoft.VisualBasic.Strings.ChrW).ToArray())

Having said all that, why are you using a GetWindowText that marshals the value back to you as a byte array rather than as a StringBuilder?

[kcvinker]

@masonwheeler ,
Thanks for the reply. To be frank, I was so frustated when i saw the result of my boo program. After posting here, today i started a new project. In this project, i compiled all this vb.net unmanaged code as a class library. Then i am trying to add it in my boo project. Anyways, now i see your reply. Let me try your suggestions.
Frankly speaking, i don't know about how to deal with this with StringBuilder. I am hobby programmer. Anyways, i will check it for sure. I am going to check it in PInvoke.Net. They sure have some samples with stringbuilder.
The code you added in your reply (Last piece of code) is not supporting in my SD. I mean i am not getting any intellisense help. So i am assuming that i am doing something wrong.