Dynamically apply where clause in Linq query in ASP.Net

Hi AjayP,

Here i have used Northwind Database. The download and install instructions are provided in the following article.

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string ContactName = "Maria";
        string Country = "Austria";
        string ShipCity = "Berlin";
        CustomersJoinDataContext ctx = new CustomersJoinDataContext();
        var strQuery = from customer in ctx.Customers
                        join order in ctx.Orders
                        on customer.CustomerID equals order.CustomerID
                        select new
                        {
                            CustomerID = customer.CustomerID,
                            CompanyName = customer.CompanyName,
                            ContactName = customer.ContactName,
                            ContactTitle = customer.ContactTitle,
                            Address = customer.Address,
                            City = customer.City,
                            Region = customer.Region,
                            PostalCode = customer.PostalCode,
                            Country = customer.Country,
                            Phone = customer.Phone,
                            Fax = customer.Fax,
                            OrderID = order.OrderID,
                            EmployeeID = order.EmployeeID,
                            OrderDate = order.OrderDate,
                            RequiredDate = order.RequiredDate,
                            ShippedDate = order.ShippedDate,
                            ShipVia = order.ShipVia,
                            Freight = order.Freight,
                            ShipName = order.ShipName,
                            ShipAddress = order.ShipAddress,
                            ShipCity = order.ShipCity,
                            ShipRegion = order.ShipRegion,
                            ShipPostalCode = order.ShipPostalCode,
                            ShipCountry = order.ShipCountry
                        };

        if (!string.IsNullOrEmpty(ContactName))
        {
            strQuery = strQuery.Where(x => x.ContactName == ContactName);
        }
        if (!string.IsNullOrEmpty(Country))
        {
            strQuery = strQuery.Where(x => x.Country == Country);
        }
        if (!string.IsNullOrEmpty(ShipCity))
        {
            strQuery = strQuery.Where(x => x.ShipCity == ShipCity);
        }

        GridView1.DataSource = strQuery;
        GridView1.DataBind();
    }
}

 HTML

<asp:GridView ID="GridView1" runat="server">
</asp:GridView>

Output