I have the following code snippet that produces a compilation error:
public List<string> batchaddresses; public MapFiles(string [] addresses) { for (int i = 0; i < addresses.Count(); i++) { batchaddresses.AddRange(Directory.GetFiles(addresses[i], "*.esy")); } } I get an error when I try to use the List<T>.AddRange() method:
Object reference not set to an instance of an object What am I doing wrong?
Where is batchaddresses initialized?
Declaring the variable does not suffice. You must initialize it, like so:
// In your constructor batchaddresses = new List<string>(); // Directly at declaration: public List<string> batchaddresses = new List<string>(); 
you have to initialize the list
List<String> batchaddresses = new List<String>();
The batchaddresses field hasn't been initialised. You can initialise it as part of the declaration:
public List<string> batchaddresses = new List<string>(); From your snippet, it doesn't look as though batchaddresses is initialised. Replace the line with this:
public List<string> batchaddresses = new List<string>(); 