How to check all properties of an object whether null or empty?

I suppose you want to make sure that all properties are filled in.

A better option is probably by putting this validation in the constructor of your class and throw exceptions if validation fails. That way you cannot create a class that is invalid; catch exceptions and handle them accordingly.

Fluent validation is a nice framework (http://fluentvalidation.codeplex.com) for doing the validation. Example:

public class CustomerValidator: AbstractValidator<Customer> 
{
    public CustomerValidator()
    {
        RuleFor(customer => customer.Property1).NotNull();
        RuleFor(customer => customer.Property2).NotNull();
        RuleFor(customer => customer.Property3).NotNull();
    }
}

public class Customer
{
    public Customer(string property1, string property2, string property3)
    {
         Property1  = property1;
         Property2  = property2;
         Property3  = property3;
         new CustomerValidator().ValidateAndThrow();
    }

    public string Property1 {get; set;}
    public string Property2 {get; set;}
    public string Property3 {get; set;}
}

Usage:

 try
 {
     var customer = new Customer("string1", "string", null);
     // logic here
 } catch (ValidationException ex)
 {
     // A validation error occured
 }

PS - Using reflection for this kind of thing just makes your code harder to read. Using validation as shown above makes it explicitly clear what your rules are; and you can easily extend them with other rules.

You can do it using Reflection

bool IsAnyNullOrEmpty(object myObject)
{
    foreach(PropertyInfo pi in myObject.GetType().GetProperties())
    {
        if(pi.PropertyType == typeof(string))
        {
            string value = (string)pi.GetValue(myObject);
            if(string.IsNullOrEmpty(value))
            {
                return true;
            }
        }
    }
    return false;
}

Matthew Watson suggested an alternative using LINQ:

return myObject.GetType().GetProperties()
    .Where(pi => pi.PropertyType == typeof(string))
    .Select(pi => (string)pi.GetValue(myObject))
    .Any(value => string.IsNullOrEmpty(value));

The following code returns if any property is not null.

  return myObject.GetType()
                 .GetProperties() //get all properties on object
                 .Select(pi => pi.GetValue(myObject)) //get value for the property
                 .Any(value => value != null); // Check if one of the values is not null, if so it returns true.