Public Class frmSquareMatrix
    Const GRANDEZZAMAT As Integer = 26
    Public matrice(GRANDEZZAMAT - 1, GRANDEZZAMAT - 1) As ULong

    Private Sub getsumenabled() ' LT violazione del principio MaiuscoleEMinuscoleNonACasaccio
        cmdGetSum.Enabled = False
        If rdbRiga.Checked = True And Val(Len(txtQuery.Text)) = 1 Or rdbColonna.Checked = True And Val(Len(txtQuery.Text)) = 1 Then
            'LT Caso mai: If Len(txtQuery.Text) = 1 And (rdbRiga.Checked Or rdbColonna.Checked) Then
            cmdGetSum.Enabled = True
        End If
    End Sub

    Private Sub chbMultiple_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) Handles chbMultiple.CheckedChanged
        txtInput.Multiline = chbMultiple.Checked
        If txtInput.Multiline Then
            txtInput.Height = 150
            txtInput.ScrollBars = ScrollBars.Vertical
        End If
    End Sub

    Private Function cordinate(ByVal input As Char) 'LT coordinate
        Return Asc(UCase(input)) - 65
    End Function

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        getsumenabled()
    End Sub

    Private Sub Cancella()  'LT Pulisci? Inizializza?
        Dim riga, colonna As Integer
        For riga = 0 To GRANDEZZAMAT - 1
            For colonna = 0 To GRANDEZZAMAT - 1
                matrice(riga, colonna) = 0
            Next
        Next
    End Sub

    Private Sub cmdClear_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cmdClear.Click
        Cancella()
    End Sub

    Private Sub cmdImport_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cmdImport.Click
        Dim ncar, riga, colonna As Integer
        Dim valorenuminput As ULong

        If Verificatesto(txtInput.Text) = True Then
            ncar = Len(txtInput.Text) - 2
            riga = Asc(UCase(Mid(txtInput.Text, 1, 1))) - 65  ' LT Hai già una funzione che fa questo, perché non usarla?
            colonna = Asc(UCase(Mid(txtInput.Text, 2, 2))) - 65
            valorenuminput = Val(Mid(txtInput.Text, 3, ncar))
            matrice(riga, colonna) = valorenuminput
        End If

        ' LT Se è abilitato il testo multilinea dovresti fare l'operazione riga per riga...

        txtInput.Text = ""
        txtInput.Focus()
    End Sub

    Private Function Verificatesto(ByVal dato As String)
        Dim risposta As Boolean
        Dim i As Integer

        If Len(dato) >= 3 And IsNumeric(Mid(txtInput.Text, 3, 3)) Then
            If UCase(Mid(dato, 1, 2)) >= "AA" And UCase(Mid(dato, 1, 2)) <= "ZZ" Then
                ' LT La stringa "A&', ad esempio, soddisfa la condizione ma non il criterio che vorresti impostare...
                For i = 3 To Len(dato)
                    If (Mid(dato, i, 1) >= "0") And (Mid(dato, i, 1) <= "9") Then
                        risposta = True
                    Else
                        risposta = False
                    End If
                    'LT Problema: basta che l'ultimo carattere sia valido e risposta sarà vero
                Next
            End If
        End If
        Return risposta
    End Function

    Private Function Sommariga(ByVal riga As Integer)
        Dim somma As ULong = 0
        Dim colonna As Integer

        For colonna = 0 To GRANDEZZAMAT - 1
            somma = somma + matrice(riga, colonna)
        Next
        Return somma
    End Function

    Private Function Sommacolonna(ByVal colonna As Integer)
        Dim somma As ULong = 0
        Dim riga As Integer

        For riga = 0 To GRANDEZZAMAT - 1
            somma = somma + matrice(riga, colonna)
        Next
        Return somma

    End Function

    Private Sub txtQuery_TextChanged(ByVal sender As Object, ByVal e As EventArgs) Handles txtQuery.TextChanged
        getsumenabled()
    End Sub

    Private Sub cmdGetSum_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGetSum.Click
        cmdGetSum.Enabled = False

        Dim somma As ULong
        Dim i As Integer = cordinate(txtQuery.Text)  ' LT perché i come nome di variabile?
        If rdbRiga.Checked Then
            somma = Sommariga(i)
        End If
        If rdbColonna.Checked Then
            somma = Sommacolonna(i)
        End If
        lblResult.Text = CStr(somma)
    End Sub

    Private Sub txtInput_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtInput.TextChanged
        cmdImport.Enabled = False
        If Verificatesto(txtInput.Text) = True Then
            cmdImport.Enabled = True
        End If
    End Sub

    Private Sub rdbRiga_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles rdbRiga.CheckedChanged
        getsumenabled()
    End Sub

    Private Sub rdbColonna_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles rdbColonna.CheckedChanged
        getsumenabled()
    End Sub
End Class