c# list find index code example

Example 1: c# get index of item in list

Array.IndexOf(arrName, searchingFor)

Example 2: c# findindex

// Lets say you have an object with tha name of 'Role' nad it has parameters
// 'Name' & 'Id'

List<Role> roles = new List<Role>();
roles.Add(new Role() { Name = "Admin", Id = 1 });
roles.Add(new Role() { Name = "User", Id = 2 });

// Using a lambda expression we can find the index of a role
// with a specific text:

int roleIndex = roles.FindIndex(
	// Note that you can also use the index if youd like
	role => role.Name == "Admin"
);

// This can also be done using a variable from outside
// the lambda expression: 

string name = "Admin";
int roleIndex = roles.FindIndex(
	// Note that you can also use the index if youd like
	role => role.Name == "name
);

if (roleIndex > -1)
{
    Console.log($"Role {roles[roleIndex].Name} +
                was found at index {roleIndex}");
}

Example 3: index of item in list C#

List<string> strings = new List<string>(){"bob","ate","an", "apple"};
strings.IndexOf("bob");
//returns 0 
strings.IndexOf("an");
//returns 2
strings.IndexOf("apple");
//returns 3
strings.IndexOf("banana");
//returns -1
//Because banana is not in the list, IndexOf() returns -1