Update ASP.Net Label after inserting record in Database on Button Click in C# and VB.Net

Hi micah,

Please refer below sample.

HTML

<div>
    <asp:DropDownList ID="ddlItemName" runat="server">
        <asp:ListItem Text="A" />
        <asp:ListItem Text="B" />
    </asp:DropDownList>
    <asp:DropDownList ID="ddlCategory" runat="server">
        <asp:ListItem Text="Alpha" />
    </asp:DropDownList>
    <asp:TextBox runat="server" ID="txtCountry" />
    <asp:Label ID="lblMessage" runat="server" />
    <asp:Button Text="Insert" runat="server" OnClick="btnsubmit_Click" />
</div>

Namespaces

C#

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

VB.Net

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

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        lblMessage.Text = GetQuantity().ToString();
    }
}

private int GetQuantity()
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT CartonQty FROM StockDemo", con))
        {
            con.Open();            
            return Convert.ToInt32(cmd.ExecuteScalar());
            con.Close();
        }
    }
}
protected void btnsubmit_Click(object sender, EventArgs e)
{
    int prequt = Convert.ToInt32(lblMessage.Text);
    int currentqut = Convert.ToInt32(txtCountry.Text);
    int totalqut = prequt - currentqut;
    int inserted = 0;
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString);
    SqlCommand cmd = new SqlCommand();
    cmd.CommandType = CommandType.Text;
    cmd.Connection = con;
    cmd.CommandText = "INSERT INTO MainWareHouse (ItemName,Category, CartonQty) VALUES(@ItemName,@Category,@CartonQty)";
    cmd.Parameters.AddWithValue("@ItemName", ddlItemName.SelectedItem.Text.Trim());
    cmd.Parameters.AddWithValue("@Category", ddlCategory.SelectedItem.Text.Trim());
    cmd.Parameters.AddWithValue("@CartonQty", totalqut);
    con.Open();
    inserted = cmd.ExecuteNonQuery();
    con.Close();

    cmd = new SqlCommand();
    cmd.CommandType = CommandType.Text;
    cmd.Connection = con;
    cmd.CommandText = "UPDATE StockDemo SET CartonQty=@CartonQty WHERE ItemName=@ItemName";
    cmd.Parameters.AddWithValue("@ItemName", ddlItemName.SelectedItem.Text.Trim());
    cmd.Parameters.AddWithValue("@CartonQty", totalqut);
    con.Open();
    inserted = cmd.ExecuteNonQuery();
    con.Close();
    lblMessage.Text = GetQuantity().ToString();
}

VB.Net

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
        If Not Me.IsPostBack Then
            lblMessage.Text = GetQuantity().ToString()
        End If
    End Sub

    Private Function GetQuantity() As Integer
        Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)

            Using cmd As SqlCommand = New SqlCommand("SELECT CartonQty FROM StockDemo", con)
                con.Open()
                Return Convert.ToInt32(cmd.ExecuteScalar())
                con.Close()
            End Using
        End Using
    End Function

    Protected Sub btnsubmit_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim prequt As Integer = Convert.ToInt32(lblMessage.Text)
        Dim currentqut As Integer = Convert.ToInt32(txtCountry.Text)
        Dim totalqut As Integer = prequt - currentqut
        Dim inserted As Integer = 0
        Dim con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Dim cmd As SqlCommand = New SqlCommand()
        cmd.CommandType = CommandType.Text
        cmd.Connection = con
        cmd.CommandText = "INSERT INTO MainWareHouse (ItemName,Category, CartonQty) VALUES(@ItemName,@Category,@CartonQty)"
        cmd.Parameters.AddWithValue("@ItemName", ddlItemName.SelectedItem.Text.Trim())
        cmd.Parameters.AddWithValue("@Category", ddlCategory.SelectedItem.Text.Trim())
        cmd.Parameters.AddWithValue("@CartonQty", totalqut)
        con.Open()
        inserted = cmd.ExecuteNonQuery()
        con.Close()
        cmd = New SqlCommand()
        cmd.CommandType = CommandType.Text
        cmd.Connection = con
        cmd.CommandText = "UPDATE StockDemo SET CartonQty=@CartonQty WHERE ItemName=@ItemName"
        cmd.Parameters.AddWithValue("@ItemName", ddlItemName.SelectedItem.Text.Trim())
        cmd.Parameters.AddWithValue("@CartonQty", totalqut)
        con.Open()
        inserted = cmd.ExecuteNonQuery()
        con.Close()
        lblMessage.Text = GetQuantity().ToString()
    End Sub

Screenshot