public static string ValidateAge(ViewModelWithErrorInfo vm, int age)
{
if (age <= 0)
{
return("Age must be positive");
}
return(null);
}
public static IDisposable SetupValidation <TProperty>(this ViewModelWithErrorInfo vm, Expression <Func <ViewModelWithErrorInfo, TProperty> > expr,
Func <ViewModelWithErrorInfo, TProperty, string> validateFunc)
{
var name = expr.GetMember();
var errorInfoType = typeof(IPropertyErrorsContainer <>).MakeGenericType(vm.GetType());
var setupValidationMethod = errorInfoType.GetMethod("SetupValidation").MakeGenericMethod(typeof(TProperty));
var result = (IDisposable)setupValidationMethod.Invoke(vm.ErrorInfo, new object[] { name, validateFunc });
return(result);
}
public static string ValidateName(ViewModelWithErrorInfo vm, string name)
{
if (string.IsNullOrWhiteSpace(name))
{
return("Name cannot be empty.");
}
if (name?.Length <= 5)
{
return("Name must be at least 6 characters long.");
}
return(null);
}
public static IDisposable SetupNameValidation(this ViewModelWithErrorInfo vm)
{
return(vm.SetupValidation <ViewModelWithErrorInfo, string>(vm.ErrorInfo, o => o.Name, ValidateName));
}
public static void ClearValidations(this ViewModelWithErrorInfo vm)
{
vm.ErrorInfo.ClearValidations();
}
public static IDisposable SetupAgeValidation(this ViewModelWithErrorInfo vm)
{
return(vm.SetupValidation <ViewModelWithErrorInfo, int>(vm.ErrorInfo, o => o.Age, ValidateAge));
}