Generate Alphanumeric UniqueId based on Windows Form ComboBox using C# and VB.Net

Hey AnkitPal,

Please refer below sample.

Namespaces

C#

using System.Data.SqlClient;

VB.Net

Imports System.Data.SqlClient

Code

C#

public Form1()
{
    InitializeComponent();
    lblNewCId.Visible = false;
}
string connStr = @"Server=.\SQL2005;DataBase=Test;UID=sa;PWD=pass@123";
private void button1_Click(object sender, EventArgs e)
{
    string previousCidQuery = "SELECT MAX(UniqueId) UniqueId FROM GenerateUniqueId";
    string newCID = GenerateNewCID(connStr, previousCidQuery);
    lblNewCId.Text = newCID.ToString();
    string insertQuery = "INSERT INTO GenerateUniqueId VALUES('" + newCID + "')";
    InsertNewCID(connStr, insertQuery);
}
private void InsertNewCID(string connection, string query)
{
    using (SqlConnection con = new SqlConnection(connection))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand(query, con);
        cmd.ExecuteNonQuery();
        con.Close();
    }
}

private string GenerateNewCID(string connection, string query)
{
    lblNewCId.Visible = true;
    string newCID = string.Empty;
    using (SqlConnection con = new SqlConnection(connection))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand(query, con);
        SqlDataReader dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            string i = dr[0].ToString();
            if (string.IsNullOrEmpty(i))
            {
                newCID = "GP" + DateTime.Now.ToString("yyMM") + ddlCSHD.Text + "1".PadLeft(6, '0');
            }
            else
            {
                i = i.Substring(10);
                int j = Convert.ToInt32(i);
                j = j + 1;
                newCID = "GP" + DateTime.Now.ToString("yyMM") + ddlCSHD.Text + j.ToString().PadLeft(6, '0'); ;
            }
        }
        con.Close();
    }

    return newCID;
}

VB.Net

Public Sub New()
    InitializeComponent()
    lblNewCId.Visible = False
End Sub

Private connStr As String = "Server=.\SQL2005;DataBase=Test;UID=sa;PWD=pass@123"
Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim previousCidQuery As String = "SELECT MAX(UniqueId) UniqueId FROM GenerateUniqueId"
    Dim newCID As String = GenerateNewCID(connStr, previousCidQuery)
    lblNewCId.Text = newCID.ToString()
    Dim insertQuery As String = "INSERT INTO GenerateUniqueId VALUES('" & newCID & "')"
    InsertNewCID(connStr, insertQuery)
End Sub

Private Sub InsertNewCID(ByVal connection As String, ByVal query As String)
    Using con As SqlConnection = New SqlConnection(connection)
        con.Open()
        Dim cmd As SqlCommand = New SqlCommand(query, con)
        cmd.ExecuteNonQuery()
        con.Close()
    End Using
End Sub

Private Function GenerateNewCID(ByVal connection As String, ByVal query As String) As String
    lblNewCId.Visible = True
    Dim newCID As String = String.Empty

    Using con As SqlConnection = New SqlConnection(connection)
        con.Open()
        Dim cmd As SqlCommand = New SqlCommand(query, con)
        Dim dr As SqlDataReader = cmd.ExecuteReader()

        While dr.Read()
            Dim i As String = dr(0).ToString()

            If String.IsNullOrEmpty(i) Then
                newCID = "GP" & DateTime.Now.ToString("yyMM") + ddlCSHD.Text & "1".PadLeft(6, "0"c)
            Else
                i = i.Substring(10)
                Dim j As Integer = Convert.ToInt32(i)
                j = j + 1
                newCID = "GP" & DateTime.Now.ToString("yyMM") + ddlCSHD.Text & j.ToString().PadLeft(6, "0"c)
            End If
        End While

        con.Close()
    End Using
    Return newCID
End Function

Screenshot