In this article I will explain with an example, how to insert ComboBox value into SQL Server database in Windows Forms (WinForms) Application using C# and VB.Net.
 
 

Database

I have made use of the following table Customers with the schema as follows.
Insert ComboBox value into Database using C# and VB.Net
 
Note: You can download the database table SQL by clicking the download link below.
           Download SQL file
 
 

Form Design

The following Form consists of:
Label – For labelling controls.
TextBox – For capturing Name to be inserted.
ComboBox – For capturing Country name to be inserted.
Insert ComboBox value into Database using C# and VB.Net
 
 

Adding ConnectionString to the App.Config file

You need to add the Connection String in the ConnectionStrings section of the App.Config file in the following way.
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <connectionStrings>
        <add name="ConString" connectionString="Data Source=Mudassar-PC\SQL2019;Initial Catalog=AjaxSamples;Integrated Security=true" />
    </connectionStrings>
</configuration>
 
 

Namespace

You will need to import the following namespaces.
C#
using System.Configuration;
using System.Data.SqlClient;
 
VB.Net
Imports System.Configuration
Imports System.Data.SqlClient
 
 

Inserting record into the Database in Windows Forms

Inside the Form Load event handler, the ComboBox items are added.
When Insert button is clicked, the Name value is fetched from the TextBox, while the Country value is fetched from the ComboBox are inserted into the SQL Server database table using ADO.Net.
Note: For more details on how to read Connection String from App.Config file, please refer my article Read (Get) Connection String from App.Config file using C# and VB.Net.
 
Finally, the TextBox and ComboBox value is set to empty and CustomerId of the inserted record is fetched and displayed in MessageBox.
C#
private void Form1_Load(object sender, EventArgs e)
{
    cbCountries.Items.Add("Please Select");
    cbCountries.Items.Add("United States");
    cbCountries.Items.Add("India");
    cbCountries.Items.Add("France");
    cbCountries.Items.Add("Russia");
}
 
private void OnInsert(object sender, EventArgs e)
{
    int customerId;
    string query = "INSERT INTO Customers (Name, Country) VALUES(@Name, @Country)";
    query += " SELECT SCOPE_IDENTITY()";
    string constring = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constring))
    {
        using (SqlCommand cmd = new SqlCommand(query))
        {
            cmd.Parameters.AddWithValue("@Name", txtName.Text);
            cmd.Parameters.AddWithValue("@Country", cbCountries.SelectedItem);
            cmd.Connection = con;
            con.Open();
            customerId = Convert.ToInt32(cmd.ExecuteScalar());
            con.Close();
        }
    }
    txtName.Text = string.Empty;
    cbCountries.Text = string.Empty;
    MessageBox.Show("Inserted Customer ID: " + customerId);
}
 
VB.Net
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    cbCountries.Items.Add("Please Select")
    cbCountries.Items.Add("United States")
    cbCountries.Items.Add("India")
    cbCountries.Items.Add("France")
    cbCountries.Items.Add("Russia")
End Sub
 
Private Sub OnInsert(ByVal sender As Object, ByVal e As EventArgs) Handles btnInsert.Click
    Dim customerId As Integer
    Dim query As String = "INSERT INTO Customers (Name, Country) VALUES(@Name, @Country)"
    query += " SELECT SCOPE_IDENTITY()"
    Dim constring As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constring)
        Using cmd As SqlCommand = New SqlCommand(query)
            cmd.Parameters.AddWithValue("@Name", txtName.Text)
            cmd.Parameters.AddWithValue("@Country", cbCountries.SelectedItem)
            cmd.Connection = con
            con.Open()
            customerId = Convert.ToInt32(cmd.ExecuteScalar())
            con.Close()
        End Using
    End Using
    txtName.Text = String.Empty
    cbCountries.Text = String.Empty
    MessageBox.Show("Inserted Customer ID: " & customerId)
End Sub
 
 

Screenshots

Insert ComboBox value into Database using C# and VB.Net
 

Record after Insert in database

Insert ComboBox value into Database using C# and VB.Net
 
 

Downloads

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