Auto-Suggest in a TextBox Using C# and SQL Server

Searching an accurate information or record in the database is very difficult without a hard copy for your basis. So, in this tutorial, I will teach you how to create a  TextBox that has an auto-suggest with C# and SQL server. With this, TextBox will automatically suggest when you begin to type into it. This is very helpful in searching of records when you only knew is the initial letter of it.

Let’s begin;

• Create a database and name it “dbname”.
• Open Microsoft Visual Studio and create new Windows Form Application.
• Do the following Form as follows.

• Go to the Solution Explorer, double click the “View Code”  to display the code editor.

• Declare all the classes and variables that are needed.

Note: Put using System.Data.SqlClient; above the namespace to access sql server library.

//initialized all classes
 SqlConnection con = new SqlConnection();
 SqlCommand cmd = new SqlCommand();
 SqlDataAdapter da = new SqlDataAdapter();
 DataTable dt = new DataTable();

//declare a variable for the query.
 string query;

• Go back to the design view, double click the Form and do the following code for making an auto-suggest TextBox and retrieving data in the SQL database.

private void Form1_Load(object sender, EventArgs e)
 {
 //Connection between SQL Server to C#
 con.ConnectionString = "Data Source=.\\SQLEXPRESS;Database=dbname;trusted_connection=true;";
 //set a query for retrieving data in the database
 query = "Select Fullname from tblname"; 
 //initialize new Sql commands
 cmd = new SqlCommand();
 //hold the data to be executed.
 cmd.Connection = con;
 cmd.CommandText = query;
 //initialize new Sql data adapter
 da = new SqlDataAdapter();
 //fetching query in the database.
 da.SelectCommand = cmd;
 //initialize new datatable
 dt = new DataTable();
 //refreshes the rows in specified range in the datasource. 
 da.Fill(dt);

textBox1.AutoCompleteCustomSource.Clear();
 foreach (DataRow r in dt.Rows)
 {
 //getting all rows in the specific field|Column
 var rw = r.Field<string>("Fullname");

//Set the properties of a textbox to make it auto suggest.
 textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
 textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource; 
 //adding all rows into the textbox
 textBox1.AutoCompleteCustomSource.Add(rw); 
 
 }

}

Output:

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