I have a WPF
application(.Net 3.5
) which uses the IDataErrorInfo
on the ViewModel to validate input.
It works great, the usercontrol get the correct UI feedback.
The problem is that the user can still change the selected element, or save this element.
So my question is: How can I know that all my properties are valid? Or at least that all my displayed values are valid. The goal is to bind some IsActive
on this result
From your comment on your implementation of IDataErrorInfo
change your implementation to this style....
#region IDataErrorInfo Members
public string Error
{
get { return this[null] }
}
public string this[string columnName]
{
get
{
StringBuilder result = new StringBuilder();
if (string.IsNullOrEmpty(columnName) || columnName == "FirstName")
{
if (string.IsNullOrEmpty(FirstName))
result.Append("Please enter a First Name\n");
}
if (string.IsNullOrEmpty(columnName) || columnName == "LastName")
{
if (string.IsNullOrEmpty(LastName))
result.Append("Please enter a Last Name\n");
}
if (string.IsNullOrEmpty(columnName) || columnName == "Age")
{
if (Age < = 0 || Age >= 99)
result.Append("Please enter a valid age\n");
}
return (result.Length==0) ? null : result.Remove(result.Length-1,1).ToString();
}
}
#endregion
public bool IsValid {
get { return string.IsNullOrEmpty(this.Error); }
}
Then in your property changed event
if (e.PropertyName == "Error") {
OnPropertyChanged(this,new PropertyChangedEventArgs("IsValid"));
}
if (e.PropertyName != "Error" && e.PropertyName != "IsValid") {
OnPropertyChanged(this,new PropertyChangedEventArgs("Error"));
}