Practical usage of Find<T> Method in Generic List<T> using Predicate

Step 1: Used Namespaces:

using System;
using System.Collections.Generic;

Step 2: Used Collection for demo:

// <summary>
/// This is static collection used in this tutorials
/// </summary>
/// <returns></returns>
private List<CompanyProduct> AddCollection()
{
list.Add(new CompanyProduct("MS Word", 1, "Microsoft", new DateTime(2012, 10, 31)));
list.Add(new CompanyProduct("MS Excel", 2, "Microsoft", new DateTime(2011, 10, 31)));
list.Add(new CompanyProduct("MS Powerpoint", 3, "Microsoft", new DateTime(2010, 10, 31)));
list.Add(new CompanyProduct("Visual Studio", 2, "Microsoft", new DateTime(2011, 10, 31)));
list.Add(new CompanyProduct("Sql Server", 3, "Microsoft", new DateTime(2010, 10, 31)));
list.Add(new CompanyProduct("Oracle", 4, "Oracle", new DateTime(2011, 10, 31)));
list.Add(new CompanyProduct("Sharepoint", 6, "Microsoft", new DateTime(2012, 10, 31)));
list.Add(new CompanyProduct("MS Outlook", 7, "Microsoft", new DateTime(2011, 10, 31)));
return list;
}

Step 3: Printing the collection:

List<CompanyProduct> list = AddCollection();
PrintList(list, "Available Collection");

Filtering the first product by company name using Predicate

//Filter the first product by company name.
CompanyProduct cp = list.Find(delegate(CompanyProduct item) { return item.CompanyName == "Microsoft"; });
Response.Write("<br/>");
Response.Write(string.Format(" Product={0} >>> CompanyName={1}",
cp.Product, cp.CompanyName));

Step 4: Filtering the first product by product id using Predicate

//Filter the first product by product id.
cp = list.Find(delegate(CompanyProduct item) { return item.ProductID == 1; });
Response.Write("<br/>");
Response.Write(string.Format(" Product={0} >>> CompanyName={1}",
cp.Product, cp.CompanyName));

Step 5: Filtering the first product by productRegisterDate using Predicate

//Filter the first product by productRegisterDate.
cp = list.Find(delegate(CompanyProduct item) { return item.ProductRegisterDate == new DateTime(2010, 10, 31); });
Response.Write("<br/>");
Response.Write(string.Format(" Product={0} >>> CompanyName={1}",
cp.Product, cp.CompanyName));

Step 6: Used for printing the results:

/// <summary>
/// This is used to display the list after editing list.
/// </summary>
private void PrintList(List<CompanyProduct> list, string header)
{
Response.Write("<br/>");
Response.Write(" " + header);
Response.Write("<br/>");

foreach (CompanyProduct cp in list)
{
//Response.Write(string.Format("Product={0} >>> ProductId={1} >>> CompanyName={2} >>> RegisterDate={3}",
// cp.Product, cp.ProductID, cp.CompanyName, cp.ProductRegisterDate));

Response.Write(string.Format(" Product={0} >>> CompanyName={1}",
cp.Product, cp.CompanyName));

Response.Write("<br/>");
}

Response.Write("<br/>");
}
}

Step 7: Used Class for Demo

class CompanyProduct
{

public CompanyProduct(string product, int productID, string companyName, DateTime productRegisterDate)
{
this.product = product;
this.productID = productID;
this.companyName = companyName;
this.productRegisterDate = productRegisterDate;
}

private string product;
public string Product
{
get { return this.product; }
set { this.product = value; }
}

private int productID;
public int ProductID
{
get { return this.productID; }
set { this.productID = value; }
}

private string companyName;
public string CompanyName
{
get { return this.companyName; }
set { this.companyName = value; }
}

private DateTime productRegisterDate;
public DateTime ProductRegisterDate
{
get { return this.productRegisterDate; }
set { this.productRegisterDate = value; }
}
}

Thanks for reading this blog. Have a nice day.