How I can find Data Annotation attributes and their parameters using reflection

Question

I have some data annotation attribute like this:

[StringLength(20, MinimumLength = 5, ErrorMessage = \"First name must be between 5 and 20 characters\")]


        

Answer 1

I assume you have something like this:

[StringLength(20, MinimumLength = 5, ErrorMessage = "First name must be between 5 and 20 characters")]
public string FirstName {get;set;}

To get the attribute and a property from it:

StringLengthAttribute strLenAttr = 
  typeof(Person).GetProperty("FirstName").GetCustomAttributes(
  typeof(StringLengthAttribute), false).Cast<StringLengthAttribute>().Single();


int maxLen = strLenAttribute.MaximumLength;