ListBox With Data From Many Tables

This article shows transferring of data from one type of Data Source to another type of Data Source.

Aim: To add ListBox items with values from multiple tables or views.

Problem:

During my Academic Project (The Event Management System) there is a situation where I needed to display the Supplier's Names from multiple Tables (such as Caterer, Manpower, and Advertisement etc.). Right now I have completed my Academic year, but after extensive efforts and guidance from many people I succeed to achieve the intended goal in a simple manner.

Some weeks ago I placed this question in the Mind Cracker Network. Here I tried to present the sample for the same portion of the code.

This article contains the simplest way to do it.

Solution:

Requirements:

• One ListBox Control to display data.
• One Command Button to Perform associated actions
• Here I take Northwind Database as Sample Database

Justification:

1. First we have to make some declarations as follows.
   
   SqlConnection Conn =new SqlConnection("Data Source=.\\SqlExpress; "
                                                 + "Initial Catalog=Northwind; Integrated security=True");
             SqlDataReader rdr;
             SqlCommand cmd;

               //The target is very simple, we just have to
               //execute simple SELECT statements with Data Reader using Command Object

2. After the declarations, execute the SELECT statement; then add each item from the Data Reader to the ListBox. To identify data from each table you can add a TABLE name as ListBox item at the beginning of the data being displayed.
   
   private void button1_Click(object sender, EventArgs e)
           {
               Conn.Open();
    
               //Supplier
               listBox1.Items.Add("-----Suppliers----");
               cmd = new SqlCommand("Select TOP(5) ContactName As PersonName from Suppliers", Conn);
               rdr = cmd.ExecuteReader();

               while (rdr.Read())
               {
                        listBox1.Items.Add(rdr.GetValue(0).ToString());
               }
               rdr.Close();

               //Customers
               listBox1.Items.Add("-----Customers----");
               cmd = new SqlCommand("Select TOP(5) ContactName As PersonName from Customers", Conn);
               rdr = cmd.ExecuteReader();
    
               while (rdr.Read())
               {
                       listBox1.Items.Add(rdr.GetValue(0).ToString());
               }
               rdr.Close();
    
                           .
                           .          
                           .
                           .
                                       .          
           }
    

3. Figure 1 shows the intended result:
   
   
   
   Figure 1

Summary:

In this article, we have seen the ListBox operation with multiple data sources in C# Programming.