How to group multiple if condition in C#?

Question

Is there any better way to do this with fewer lines of code? Sometimes FirstName or SecondName or ThirdName values could be null - this code works but I want to improve the quality.

if (FirstName != null)
{
    txtEngageeName.Text = FirstName.ToString() ;
}
if (FirstName != null && SecondName != null)
{
    txtEngageeName.Text = FirstName.ToString() + SecondName.ToString();
}
if (FirstName != null && SecondName != null && ThirdName != null)
{
    txtEngageeName.Text = FirstName.ToString() + SecondName.ToString() + ThirdName.ToString();
}

Answer 1

You can do simple (if you really don't want spaces between entities):

txtEngageeName.Text = string.Format("{0}{1}{2}", FirstName, SecondName, ThirdName);

Nulls will be formatted as empty string.

If you need spaces.

txtEngageeName.Text = string.Join(" ", new[] { FirstName, SecondName, ThirdName}.Where(s => s != null));