Hi Vincenzo67,

Refer below sample.

I have refer below article link.

Call MySql Stored Procedure with Parameters in ASP.Net, C# and VB.Net

StoredProcedure

MySQL

DELIMITER $$
create DEFINER=`root`@`localhost` PROCEDURE `Customers_GetCustomerCountry`(IN custId INT)
BEGIN
       SELECT Country
       FROM Customers
       WHERE CustomerId = custId;
END$$
DELIMITER ;

HTML

<div>
    Search:
    <asp:TextBox ID="txtCustomerId" runat="server" Text="" />
    <asp:Button Text="Search" runat="server" OnClick="Search" />
    <hr />
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
        <Columns>
            <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150" />
        </Columns>
    </asp:GridView>
</div>

Namespaces

C#

using System.Data;
using System.Configuration;
using MySql.Data.MySqlClient;

VB.Net

Imports System.Data
Imports System.Configuration
Imports MySql.Data.MySqlClient

Code

C#

protected void Search(object sender, EventArgs e)
{
    this.GetCustomer(int.Parse(txtCustomerId.Text.Trim()));
}

private void GetCustomer(int customerId)
{
    // Creating a dynamic datatable.
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] { new DataColumn("Country") });
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (MySqlConnection con = new MySqlConnection(constr))
    {
        using (MySqlCommand cmd = new MySqlCommand("Customers_GetCustomerCountry", con))
        {
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@CustId", customerId);
            con.Open();
            // Creating a variable country and it is getting the value from ExecuteScalar.
            string country = (cmd.ExecuteScalar()).ToString();
            //Inserting the value of variable into dynamic datatable.
            dt.Rows.Add(country);
            GridView1.DataSource = dt;
            GridView1.DataBind();
            con.Close();
        }
    }
}

VB.Net

Protected Sub Search(ByVal sender As Object, ByVal e As EventArgs)
    Me.GetCustomer(Integer.Parse(txtCustomerId.Text.Trim()))
End Sub

Private Sub GetCustomer(ByVal customerId As Integer)
    'Creating a dynamic datatable.
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn() {New DataColumn("Country")})
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As MySqlConnection = New MySqlConnection(constr)
        Using cmd As MySqlCommand = New MySqlCommand("Customers_GetCustomerCountry", con)
            cmd.CommandType = CommandType.StoredProcedure
            cmd.Parameters.AddWithValue("@CustId", customerId)
            con.Open()
            'Creating a variable country and it is getting the value from ExecuteScalar.
            Dim country As String = (cmd.ExecuteScalar()).ToString()
            'Inserting the value of variable into dynamic datatable.
            dt.Rows.Add(country)
            GridView1.DataSource = dt
            GridView1.DataBind()
            con.Close()
        End Using
    End Using
End Sub

Screenshot