Update Database table using ASP.Net GridView using C# and VB.Net

Hi Vincenzo67,

Please refer below sample.

Database

I have made use of the following table Customers with the schema as follows.

I have already inserted few records in the table.

You can download the database table SQL by clicking the download link below.

Download SQL file

HTML

<form id="form1" runat="server">
    <asp:GridView ID="gvCustomers" runat="server" EmptyDataText="No data" EnableViewState="true" AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound">
        <Columns>
            <asp:BoundField DataField="CustomerId" HeaderText="Id" />
            <asp:BoundField DataField="Name" HeaderText="Name" />
            <asp:TemplateField HeaderText="Country">
                <ItemTemplate>
                    <asp:DropDownList ID="ddlCountry" runat="server" AutoPostBack="true" OnSelectedIndexChanged="OnSelectedIndexChanged">
                        <asp:ListItem Text="United States" Value="1"></asp:ListItem>
                        <asp:ListItem Text="India" Value="2"></asp:ListItem>
                        <asp:ListItem Text="France" Value="3"></asp:ListItem>
                        <asp:ListItem Text="Russia" Value="4"></asp:ListItem>
                    </asp:DropDownList>
                    <asp:HiddenField ID="hfCountry" runat="server" Value='<%#Eval("Country") %>' />
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
</form>

Namespaces

C#

using System.Data;
using System.Configuration;
using System.Data.SqlClient;

VB.Net

Imports System.Data
Imports System.Configuration
Imports System.Data.SqlClient

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindGrid();
    }
}

private void BindGrid()
{
    string constring = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constring))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT CustomerId, Name, Country FROM Customers", con))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                using (DataTable dt = new DataTable())
                {
                    sda.Fill(dt);
                    gvCustomers.DataSource = dt;
                    gvCustomers.DataBind();
                }
            }
        }
    }
}

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        HiddenField hfcountry = (e.Row.FindControl("hfCountry")) as HiddenField;
        DropDownList ddlCountries = (e.Row.FindControl("ddlCountry") as DropDownList);
        string constring = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constring))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT DISTINCT Country FROM Customers", con))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);
                        ddlCountries.DataSource = dt;
                        ddlCountries.DataTextField = "Country";
                        ddlCountries.DataValueField = "Country";
                        ddlCountries.DataBind();
                        ddlCountries.Items.FindByValue(hfcountry.Value).Selected = true;
                    }
                }
            }
        }
    }
}

protected void OnSelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList ddl = (DropDownList)sender;
    GridViewRow row = (GridViewRow)ddl.NamingContainer;
    int customerid = int.Parse(row.Cells[0].Text);
    string constring = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constring))
    {
        using (SqlCommand cmd = new SqlCommand("UPDATE Customers SET Country=@Country WHERE CustomerId=@CustomerId", con))
        {
            cmd.Parameters.AddWithValue("@Country", ddl.SelectedItem.Text);
            cmd.Parameters.AddWithValue("@CustomerId", customerid);
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
    this.BindGrid();
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.BindGrid()
    End If
End Sub

Private Sub BindGrid()
    Dim constring As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString

    Using con As SqlConnection = New SqlConnection(constring)

        Using cmd As SqlCommand = New SqlCommand("SELECT CustomerId, Name, Country FROM Customers", con)

            Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)

                Using dt As DataTable = New DataTable()
                    sda.Fill(dt)
                    gvCustomers.DataSource = dt
                    gvCustomers.DataBind()
                End Using
            End Using
        End Using
    End Using
End Sub

Protected Sub OnRowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim hfcountry As HiddenField = TryCast((e.Row.FindControl("hfCountry")), HiddenField)
        Dim ddlCountries As DropDownList = (TryCast(e.Row.FindControl("ddlCountry"), DropDownList))
        Dim constring As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString

        Using con As SqlConnection = New SqlConnection(constring)

            Using cmd As SqlCommand = New SqlCommand("SELECT DISTINCT Country FROM Customers", con)

                Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)

                    Using dt As DataTable = New DataTable()
                        sda.Fill(dt)
                        ddlCountries.DataSource = dt
                        ddlCountries.DataTextField = "Country"
                        ddlCountries.DataValueField = "Country"
                        ddlCountries.DataBind()
                        ddlCountries.Items.FindByValue(hfcountry.Value).Selected = True
                    End Using
                End Using
            End Using
        End Using
    End If
End Sub

Protected Sub OnSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    Dim ddl As DropDownList = CType(sender, DropDownList)
    Dim row As GridViewRow = CType(ddl.NamingContainer, GridViewRow)
    Dim customerid As Integer = Integer.Parse(row.Cells(0).Text)
    Dim constring As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString

    Using con As SqlConnection = New SqlConnection(constring)

        Using cmd As SqlCommand = New SqlCommand("UPDATE Customers SET Country=@Country WHERE CustomerId=@CustomerId", con)
            cmd.Parameters.AddWithValue("@Country", ddl.SelectedItem.Text)
            cmd.Parameters.AddWithValue("@CustomerId", customerid)
            con.Open()
            cmd.ExecuteNonQuery()
            con.Close()
        End Using
    End Using

    Me.BindGrid()
End Sub

Screenshot