Check comma separated value exists in database using C# and VB.Net in ASP.Net

Hi tjbowesfolio,

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

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

<asp:TextBox ID="txtSearch" runat="server" TextMode="MultiLine" Height="100px"></asp:TextBox><br />
<asp:Button Text="Search" runat="server" OnClick="Search" />
<hr />
<asp:GridView ID="gvCustomers" runat="server" AutoGenerateColumns="true" AllowPaging="true"
    OnPageIndexChanging="OnPaging">
</asp:GridView>

Namespaces

C#

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

VB.Net

Imports System.Configuration
Imports System.Data.SqlClient

Code

C#

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

protected void Search(object sender, EventArgs e)
{
    this.SearchCustomers();
}

protected void OnPaging(object sender, GridViewPageEventArgs e)
{
    gvCustomers.PageIndex = e.NewPageIndex;
    this.SearchCustomers();
}

private void SearchCustomers()
{
    if (!string.IsNullOrEmpty(txtSearch.Text.Trim()))
    {
        List<string> customerIds = new List<string>();
        char[] characters = { ',', '\n' };
        string[] ids = txtSearch.Text.Trim().Split(characters, StringSplitOptions.RemoveEmptyEntries);
        for (int i = 0; i < ids.Length; i++)
        {
            if (!string.IsNullOrEmpty(ids[i].Trim()))
            {
                if (!IdExist(ids[i].Trim()))
                {
                    customerIds.Add(ids[i].Trim() + " — allowed");
                }
                else
                {
                    customerIds.Add(ids[i].Trim() + " — exluded");
                }
            }
        }
        gvCustomers.DataSource = customerIds;
        gvCustomers.DataBind();
    }
}

private bool IdExist(string id)
{
    bool isExist = false;
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "SELECT CustomerId FROM Customers WHERE CustomerId = @Id";
            cmd.Connection = con;
            cmd.Parameters.AddWithValue("@Id", id);
            con.Open();
            isExist = Convert.ToString(cmd.ExecuteScalar()) == "" ? true : false;
            con.Close();
        }
    }

    return isExist;
}

VB.Net

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

Protected Sub Search(sender As Object, e As EventArgs)
    Me.SearchCustomers()
End Sub

Protected Sub OnPaging(sender As Object, e As GridViewPageEventArgs)
    gvCustomers.PageIndex = e.NewPageIndex
    Me.SearchCustomers()
End Sub

Private Sub SearchCustomers()
    If Not String.IsNullOrEmpty(txtSearch.Text.Trim()) Then
        Dim customerIds As List(Of String) = New List(Of String)()
        Dim characters As Char() = {","c, vbLf}
        Dim ids As String() = txtSearch.Text.Trim().Split(characters, StringSplitOptions.RemoveEmptyEntries)
        For i As Integer = 0 To ids.Length - 1
            If Not String.IsNullOrEmpty(ids(i).Trim()) Then
                If Not IdExist(ids(i).Trim()) Then
                    customerIds.Add(ids(i).Trim() & " — allowed")
                Else
                    customerIds.Add(ids(i).Trim() & " — exluded")
                End If

            End If
        Next
        gvCustomers.DataSource = customerIds
        gvCustomers.DataBind()
    End If
End Sub

Private Function IdExist(ByVal id As String) As Boolean
    Dim isExist As Boolean = False
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand()
            cmd.CommandText = "SELECT CustomerId FROM Customers WHERE CustomerId = @Id"
            cmd.Connection = con
            cmd.Parameters.AddWithValue("@Id", id)
            con.Open()
            isExist = If(Convert.ToString(cmd.ExecuteScalar()) = "", True, False)
            con.Close()
        End Using
    End Using

    Return isExist
End Function

Screenshot