C# Deferred Property Setting
I am working on a project where I need to queue up a number of property changes. Let say I have:
public class foo
{
string bar { get; set; }
int bar1 { get; set }
}
I want to have some code that looks like:
//Store value set actions in a queue
foo.SetValue(bar, "abc");
foo.SetValue(bar1, 123);
//Previ开发者_StackOverflowew changes
foreach(Item change in foo.ChangeQueue)
{
Console.Write(change.PropertyName.ToString());
Console.Write(change.Value.ToString());
}
//Apply actions
foo.CommitChanges();
What is the best way to accomplish this?
You can use Dictionary<string,object>
as ChangeQueue to store your values.
You can iterate as,
foreach(KeyValuePair<string,object> item in ChangeQueue){
Console.WriteLine(item.Key);// name of property
Console.WriteLine(item.Value); // value of property
}
public void SetValue(string name, object value){
PropertyInfo p = this.GetType().GetProperty(name);
// following convert and raise an exception to preserve type safety
ChangeQueue[name] = Convert.ChangeType(value,p.PropertyType);
}
public void ApplyChanges(){
foreach(KeyValuePair<string,object> item in ChangeQueue){
PropertyInfo p = this.GetType().GetProperty(item.Key);
p.SetValue(this, item.Value, null);
}
}
"Type-safe" version which uses callbacks. This will not automatically remove duplicate-settings. It also does not use reflection and so property-name errors will fail on compilation. This method could be expanded to require a "name" and remove duplicates by using a Dictionary backing (as per Akash's answer) or allow the "setter" to return a value (such as success or failure or the old value, or whatnot).
interface Setter {
void Apply();
}
class Setter<T> : Setter {
public T Data;
public Action<T> SetFn;
public void Apply() {
SetFn(Data);
}
}
List<Setter> changeQueue = new List<Setter>();
void SetValue<T>(Action<T> setFn, T data){
changeQueue.Add(new Setter<T> {
Data = data,
SetFn = setFn,
});
}
void ApplyChanges(){
foreach (var s in changeQueue){
s.Apply();
}
}
// .. later on
SetValue(x => System.Console.WriteLine(x), "hello world!");
ApplyChanges();
This method can also be trivially used "outside" the objects being monitored because all the operations are in potential closures.
Happy coding.
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