Verify record exists in another table before delete in ASP.Net using C# and VB.Net

Hi smile,

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

HTML

<asp:TextBox runat="server" ID="txtStoreID" />
<asp:Button Text="Delete" runat="server" OnClick="OnDelete" />

Namespaces

C#

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

VB.Net

Imports System.Configuration
Imports System.Data.SqlClient

Code

C#

protected void OnDelete(object sender, EventArgs e)
{
    string isExist = "";
    string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    string query = "SELECT COUNT(*) FROM tblStore WHERE StoreTypeID = @Id";
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlCommand cmd = new SqlCommand(query))
        {
            cmd.Connection = con;
            cmd.Parameters.AddWithValue("@Id", txtStoreID.Text.Trim());
            con.Open();
            isExist = Convert.ToString(cmd.ExecuteScalar());
            con.Close();
        }
    }

    if (!string.IsNullOrEmpty(isExist))
    {
        ClientScript.RegisterClientScriptBlock(this.GetType(), "", "alert('First delete record from child table then delete record from the parent table.')", true);
    }
    else
    {
        query = "DELETE FROM tblStoreType WHERE StoreTypeID = @Id";
        using (SqlConnection con = new SqlConnection(conString))
        {
            using (SqlCommand cmd = new SqlCommand(query))
            {
                cmd.Connection = con;
                cmd.Parameters.AddWithValue("@Id", txtStoreID.Text.Trim());
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
        }
    }
}

VB.Net

Protected Sub OnDelete(ByVal sender As Object, ByVal e As EventArgs)
    Dim isExist As String = ""
    Dim conString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Dim query As String = "SELECT COUNT(*) FROM tblStore WHERE StoreTypeID = @Id"
    Using con As SqlConnection = New SqlConnection(conString)
        Using cmd As SqlCommand = New SqlCommand(query)
            cmd.Connection = con
            cmd.Parameters.AddWithValue("@Id", txtStoreID.Text.Trim())
            con.Open()
            isExist = Convert.ToString(cmd.ExecuteScalar())
            con.Close()
        End Using
    End Using

    If Not String.IsNullOrEmpty(isExist) Then
        ClientScript.RegisterClientScriptBlock(Me.GetType(), "", "alert('First delete record from child table then delete record from the parent table.')", True)
    Else
        query = "DELETE FROM tblStoreType WHERE StoreTypeID = @Id"
        Using con As SqlConnection = New SqlConnection(conString)
            Using cmd As SqlCommand = New SqlCommand(query)
                cmd.Connection = con
                cmd.Parameters.AddWithValue("@Id", txtStoreID.Text.Trim())
                con.Open()
                cmd.ExecuteNonQuery()
                con.Close()
            End Using
        End Using
    End If
End Sub