Display Message while Insert duplicate values in Database using C# and VB.Net in ASP.Net

Hi micah,

Check this example. Now please take its reference and correct your code.

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

Name: <asp:TextBox runat="server" ID="txtName" /><br />
Country: <asp:TextBox runat="server" ID="txtCountry" /><br />
<asp:Button Text="Submit" runat="server" ID="btnSubmit" OnClick="Submit_Click" />

Namespaces

C#

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

VB.Net

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

Code

C#

protected void Submit_Click(object sender, EventArgs e)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConString"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT Name FROM Customers WHERE Name = @Name AND Country = @Country", con))
        {
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@Name", this.txtName.Text.Trim());
            cmd.Parameters.AddWithValue("@Country", this.txtCountry.Text.Trim());
            con.Open();
            string result = Convert.ToString(cmd.ExecuteScalar());
            con.Close();
            if (string.IsNullOrEmpty(result))
            {
                Insert(this.txtName.Text.Trim(), this.txtCountry.Text.Trim());
                this.txtName.Text = "";
                this.txtCountry.Text = "";
                ScriptManager.RegisterStartupScript(this, this.GetType(), "Alert", "alert('Data Submitted Successfully ... !!')", true);
            }
            else
            {
                ScriptManager.RegisterStartupScript(this, this.GetType(), "Alert", "alert('Record Already Exists');", true);
            }
        }
    }
}

private void Insert(string name, string country)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConString"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("INSERT INTO Customers VALUES (@Name, @Country)", con))
        {
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@Name", name);
            cmd.Parameters.AddWithValue("@Country", country);
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
}

VB.Net

Protected Sub Submit_Click(ByVal sender As Object, ByVal e As EventArgs)
    Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("ConString").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("SELECT Name FROM Customers WHERE Name = @Name AND Country = @Country", con)
            cmd.CommandType = CommandType.Text
            cmd.Parameters.AddWithValue("@Name", Me.txtName.Text.Trim())
            cmd.Parameters.AddWithValue("@Country", Me.txtCountry.Text.Trim())
            con.Open()
            Dim result As String = Convert.ToString(cmd.ExecuteScalar())
            con.Close()
            If String.IsNullOrEmpty(result) Then
                Insert(Me.txtName.Text.Trim(), Me.txtCountry.Text.Trim())
                Me.txtName.Text = ""
                Me.txtCountry.Text = ""
                ScriptManager.RegisterStartupScript(Me, Me.GetType(), "Alert", "alert('Data Submitted Successfully ... !!')", True)
            Else
                ScriptManager.RegisterStartupScript(Me, Me.GetType(), "Alert", "alert('Record Already Exists');", True)
            End If
        End Using
    End Using
End Sub

Private Sub Insert(ByVal name As String, ByVal country As String)
    Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("ConString").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("INSERT INTO Customers VALUES (@Name, @Country)", con)
            cmd.CommandType = CommandType.Text
            cmd.Parameters.AddWithValue("@Name", name)
            cmd.Parameters.AddWithValue("@Country", country)
            con.Open()
            cmd.ExecuteNonQuery()
            con.Close()
        End Using
    End Using
End Sub

Screenshot