AutoIncrement Alphanumeric

Hi,

Please refer below code.

HTML

<div>
    <asp:TextBox ID="txtAlphabet" runat="server" />
    <asp:Button Text="Increament" runat="server" OnClick="Increament" />
    <br />
    <asp:Label ID="lblResult" runat="server" />
</div>

C#

protected void Increament(object sender, EventArgs e)
{
    if (!string.IsNullOrEmpty(txtAlphabet.Text))
    {
        lblResult.Text = increament(txtAlphabet.Text);
    }
}

public string increament(string number)
{
    number = number.Trim();
    int result;
    bool isNumber = int.TryParse(number, out result);
    if (isNumber)
    {
        result = result + 1;
        return result.ToString();
    }
    else
    {
        if (number.Length == 1)
        {
            char aplpha = number[0];
            if (aplpha == 'z')
            {
                aplpha = 'a';
            }
            else if (aplpha == 'Z')
            {
                aplpha = 'A';
            }
            else
            {
                aplpha++;
            }
            return aplpha.ToString();
        }
        else
        {

            int index = -1;
            foreach (Match match in Regex.Matches(number, "[a-zA-Z]"))
            {
                index = match.Index;
            }
            string aphabet = number.Substring(index, 1);
            string next = string.Empty;
            int nextNum = default(int);
            if (index != number.Length - 1)
            {
                next = number.Substring(index + 1, number.Length - 1 - index);
                nextNum = Convert.ToInt32(next);
            }
            char aplpha = aphabet[0];
            if (nextNum >= 9 || (nextNum == 0 && index == number.Length - 1))
            {
                if (aplpha == 'z')
                {
                    aplpha = 'a';
                }
                else if (aplpha == 'Z')
                {
                    aplpha = 'A';
                }
                else
                {
                    aplpha++;
                }
                nextNum = 0;
            }
            else
            {
                nextNum++;
            }
            return index != number.Length - 1 ? string.Format("{0}{1}{2}", number.Substring(0, index), aplpha, nextNum) : string.Format("{0}{1}", number.Substring(0, index), aplpha);
        }
    }
}

VB

Protected Sub Increament(sender As Object, e As EventArgs)
    If Not String.IsNullOrEmpty(txtAlphabet.Text) Then
        lblResult.Text = increament(txtAlphabet.Text)
    End If
End Sub

Public Function increament(number As String) As String
    number = number.Trim()
    Dim result As Integer
    Dim isNumber As Boolean = Integer.TryParse(number, result)
    If isNumber Then
        result = result + 1
        Return result.ToString()
    Else
        If number.Length = 1 Then
            Dim aplpha As Char = number(0)
            If aplpha = "z"C Then
                aplpha = "a"C
            ElseIf aplpha = "Z"C Then
                aplpha = "A"C
            Else
                aplpha += 1
            End If
            Return aplpha.ToString()
        Else

            Dim index As Integer = -1
            For Each match As Match In Regex.Matches(number, "[a-zA-Z]")
                index = match.Index
            Next
            Dim aphabet As String = number.Substring(index, 1)
            Dim [next] As String = String.Empty
            Dim nextNum As Integer = 0
            If index <> number.Length - 1 Then
                [next] = number.Substring(index + 1, number.Length - 1 - index)
                nextNum = Convert.ToInt32([next])
            End If
            Dim aplpha As Char = aphabet(0)
            If nextNum >= 9 OrElse (nextNum = 0 AndAlso index = number.Length - 1) Then
                If aplpha = "z"C Then
                    aplpha = "a"C
                ElseIf aplpha = "Z"C Then
                    aplpha = "A"C
                Else
                    aplpha += 1
                End If
                nextNum = 0
            Else
                nextNum += 1
            End If
            Return If(index <> number.Length - 1, String.Format("{0}{1}{2}", number.Substring(0, index), aplpha, nextNum), String.Format("{0}{1}", number.Substring(0, index), aplpha))
        End If
    End If

End Function

Screenshot