Filter List Using Linq in C# and VB.Net

Hi sanvi,

Refer below sample.

HTML

Name :
<asp:TextBox runat="server" ID="txtName" AutoPostBack="True" OnTextChanged="Search" />
<br />
<asp:GridView runat="server" ID="gvCustomers" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="CustomerId" HeaderText="CustomerId" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:BoundField DataField="Country" HeaderText="Country" />
    </Columns>
</asp:GridView>
<br />
<asp:GridView runat="server" ID="GridView1" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Name" HeaderText="Name" />
    </Columns>
</asp:GridView>

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        List<Customers> customes = ListOfCustomers();
        gvCustomers.DataSource = customes;
        gvCustomers.DataBind();
    }
}

private static List<Customers> ListOfCustomers()
{
    List<Customers> customes = new List<Customers>
        {
            new Customers { CustomerId = 1, Name = "John Hammond",Country="United States" },
            new Customers { CustomerId = 2, Name = "Mudassar Khan" ,Country="India"},
            new Customers { CustomerId = 3, Name = "Robert",Country="France" },
            new Customers { CustomerId = 4, Name = "Suzanne Mathews" ,Country="Russia"},
        };
    return customes;
}

protected void Search(object sender, EventArgs e)
{
    List<Customers> customes = ListOfCustomers();
    var query = customes.Where(x => x.Name == txtName.Text).Select(fetch => new Customers { Name = fetch.Name });
    GridView1.DataSource = query;
    GridView1.DataBind();
}

public class Customers
{
    public int CustomerId { get; set; }
    public string Name { get; set; }
    public string Country { get; set; }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim customes As List(Of Customers) = ListOfCustomers()
        gvCustomers.DataSource = customes
        gvCustomers.DataBind()
    End If
End Sub

Private Shared Function ListOfCustomers() As List(Of Customers)
    Dim customes As List(Of Customers) = New List(Of Customers) From {
        New Customers With {
            .CustomerId = 1,
            .Name = "John Hammond",
            .Country = "United States"
        },
        New Customers With {
            .CustomerId = 2,
            .Name = "Mudassar Khan",
            .Country = "India"
        },
        New Customers With {
            .CustomerId = 3,
            .Name = "Robert",
            .Country = "France"
        },
        New Customers With {
            .CustomerId = 4,
            .Name = "Suzanne Mathews",
            .Country = "Russia"
        }
    }
    Return customes
End Function

Protected Sub Search(ByVal sender As Object, ByVal e As EventArgs)
    Dim customes As List(Of Customers) = ListOfCustomers()
    Dim query = customes.Where(Function(x) x.Name = txtName.Text).[Select](Function(fetch) New Customers With {
        .Name = fetch.Name
    })
    GridView1.DataSource = query
    GridView1.DataBind()
End Sub

Public Class Customers
    Public Property CustomerId As Integer
    Public Property Name As String
    Public Property Country As String
End Class

Screenshot