IDataErrorInfo reduce redundancy

Question

A code contains some redundant data how do i remove redundancy and simplify my code without changing its functionality..

Also i wanted to know the right way of implementing IDataErrorInfo

public string Error and public string this[string columnName] both property does the work of checking null values i dont want both to check for nulls.

Answer 1

In general it's better to use validation attributes for that, but if speak about your concrete example - you can remove redundancy like this:

public string Error
{
    get { return this[null]; }
}

public string this[string columnName]
{
    get
    {                    
        if (columnName == null || columnName == "UnitCode") {
            if (String.IsNullOrEmpty(UnitCode)) {
                return "Unit Code cannot be empty";
            }
        }
        if (columnName == null || columnName == "UnitName") {
            if (string.IsNullOrEmpty(UnitName)) {
                return "Unit Name cannot be Empty";
            }
        }
        return null;
    }
}