Search (Filter) GridView with comma separated value 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

Search Customer:   
<asp:TextBox ID="txtSearch" runat="server" TextMode="MultiLine" Height="100px"></asp:TextBox>
<asp:Button Text="Search" runat="server" OnClick="Search" />
<hr />
<asp:GridView ID="gvCustomers" runat="server" AutoGenerateColumns="false" AllowPaging="true"
    OnPageIndexChanging="OnPaging">
    <Columns>
        <asp:BoundField DataField="CustomerID" HeaderText="Id" />
        <asp:BoundField DataField="ContactName" HeaderText="Name" />
        <asp:BoundField DataField="City" HeaderText="City" />
        <asp:BoundField DataField="Country" HeaderText="Country" />
    </Columns>
</asp:GridView>

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 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()
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            string sql = "SELECT CustomerId, ContactName, City, Country FROM Customers";
            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++)
                {
                    customerIds.Add(ids[i].Trim());
                }

                sql += " WHERE CustomerID IN ('" + string.Join("','", customerIds.ToArray()) + "')";
            }
            cmd.CommandText = sql;
            cmd.Connection = con;
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                DataTable dt = new DataTable();
                sda.Fill(dt);
                gvCustomers.DataSource = dt;
                gvCustomers.DataBind();
            }
        }
    }
}

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()
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand()
            Dim sql As String = "SELECT CustomerId, ContactName, City, Country FROM Customers"
            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
                    customerIds.Add(ids(i).Trim())
                Next
                sql += " WHERE CustomerID IN ('" & String.Join("','", customerIds.ToArray()) & "')"
            End If
            cmd.CommandText = sql
            cmd.Connection = con
            Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                Dim dt As DataTable = New DataTable()
                sda.Fill(dt)
                gvCustomers.DataSource = dt
                gvCustomers.DataBind()
            End Using
        End Using
    End Using
End Sub

Screenshot