I have a UI with some controls in it bound to Person class. Whenever user enters a new information business logic need to check the database if such a person exist. If not I need to give message to user and mark that textbox like it has error(red frame around the box). My Question is can I do that on the getter or setter of the property that gives Validation error?
Thanks for the help!
using IDataErrorInfo , you can do this as follows,
public class Person : IDataErrorInfo
{
private int age;
public int Age
{
get { return age; }
set { age = value; }
}
public string Error
{
get
{
return null;
}
}
public string this[string name]
{
get
{
string result = null;
if (name == "Age")
{
if (this.age < 0 || this.age > 150)
{
result = "Age must not be less than 0 or greater than 150.";
}
}
return result;
}
}
}
in XAML Binding as follows,
<Binding Source="{StaticResource data}" Path="Age"
UpdateSourceTrigger="PropertyChanged"
ValidatesOnDataErrors="True" />
your VM should implement IDataErrorInfo and set ValidatesOnDataError=True in your Binding. Then you can validate in your ViewModel if such a person exists.
I encountered kind of the same problem when learning to use Validations wit WPF I found help through this tutorial, hope it can help you too!
