vb.net character counting

[joester007]

How do I count characters using substing and a do while loop?
Im trying to make a pogram that will allow the user to type in a phrase and when they click on the search button an inputbox will appear asking for what character to search for. The user types the character in and then a messagebox should tell him how many times the character appears in the phrase. I'm having trouble counting the characters. I have to use substring and do while.

  Dim keyword As Char
        Dim intCounter As Integer = 0
        Dim strUserInput As String = ""
        Dim txtlength As Integer
        strUserInput = CStr(txtSearch.Text)
        txtlength = strUserInput.Length()
        txtlength = AscW(keyword)
        keyword = CChar(InputBox("What charater are you looking for?", "Search"))
        Do While txtlength > intCounter

            txtSearch.Text.Substring(0, 1)
            MessageBox.Show("the character " & keyword & " appears " & intCounter & " times")
            intCounter += 1


        Loop


    End Sub

[ddanbe]

Your text could be considered as an array, Just walk through the array with a for loop and comare each char with the lookup char.

[joester007]

That's just it, my professo wants us to use substring and do while loop.

[ddanbe]

Loop through the string to get every char with Substring(counter, 1)
Counter goes from zero to stringlength-1.

[joester007]

This is what I came up with instead. This works perfectly.

    Private Sub btnSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSearch.Click
        'Declaring variables 
        Dim character As Char
        Dim intCounter As Integer = 0
        Dim strUserInput As String = ""
        Dim lengthofTxt, totalChar As Integer
        lengthofTxt = CInt(txtSearch.Text.Length)
        Try
            strUserInput = ((InputBox("What charater are you looking for?", "Search")))
            'If the user does not enter a character or enters more than one character, a messagebox will appear.
            'If the enters a wrong character then a messagebox will appear saying no match found, if the user does
            'enter the right character a messagebox will appear saying the amount of times that character appears.
            If CBool(CInt(strUserInput.Length > 1) Or CInt(strUserInput.Length = 0)) Then
                MessageBox.Show("Please enter one character.")

            Else : character = CChar((strUserInput))
                Do Until lengthofTxt = intCounter
                    If txtSearch.Text.Substring(intCounter, 1) = character Then
                        totalChar += 1
                    End If
                    intCounter += 1
                Loop
                If totalChar <> 0 Then
                    MessageBox.Show("The character " & character & " was found " & totalChar & " times.")

                Else

                    MessageBox.Show("There was no match found.")
                End If
            End If
        Catch e1 As OverflowException
            MessageBox.Show("Number too large.")
        Catch e2 As Exception
            MessageBox.Show("An error has occured" & ControlChars.Cr & " please try again")
        End Try

    End Sub