C# dynamically set property

Question

Possible Duplicate:
.Net - Reflection set object property
Setting a property by reflection with a string value

I have an object with multiple properties. Let's call the object objName. I'm trying to create a method that simply updates the object with the new property values.

I want to be able to do the following in a method:

private void SetObjectProperty(string propertyName, string value, ref object objName)
{
    //some processing on the rest of the code to make sure we actually want to set this value.
    objName.propertyName = value
}

and finally, the call:

SetObjectProperty("nameOfProperty", textBoxValue.Text, ref objName);

Hope the question is fleshed out enough. Let me know if you need more details.

Thanks for the answers all!

@DavidArcher there is no `rel` keyboard in C#...I take it you mean `ref`? There is no need to pass an object as `ref` unless you intend on changing the actual instance of it. — James, Oct 19 '12 at 08:55
Indeed, I did mean ref, and yes, I do intend on changing the actual instance. — David Archer, Oct 19 '12 at 09:00

score 79 · Accepted Answer · answered Oct 19 '12 at 08:41

79

objName.GetType().GetProperty("nameOfProperty").SetValue(objName, objValue, null)

answered Oct 19 '12 at 08:41

josejuan

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3

You should use `propertyName` inside `GetProperty()`. – Anonymous Oct 19 '12 at 08:47
2

And what if "*nameOfProperty*" doesn't exist? – James Oct 19 '12 at 09:16
1

Exception of course, you can use GetProperties to test. – josejuan Oct 22 '12 at 08:59
I was able to replace my 200 line code with 5 lines using your code sample. Thanks, you saved my day. – Ananda Dec 28 '15 at 13:16

James · Answer 2 · 2012-10-19T08:44:29.173

45

You can use Reflection to do this e.g.

private void SetObjectProperty(string propertyName, string value, object obj)
{
    PropertyInfo propertyInfo = obj.GetType().GetProperty(propertyName);
    // make sure object has the property we are after
    if (propertyInfo != null)
    {
        propertyInfo.SetValue(obj, value, null);
    }
}

edited Oct 19 '12 at 08:44

answered Oct 19 '12 at 08:38

James

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Props for checking for null before calling. – Chason Arthur Jul 29 '16 at 15:05
2

I usually also check for "can write": `if (propertyInfo != null && propertyInfo.CanWrite)`. – fdelia Apr 18 '18 at 07:16

score 4 · Answer 3 · edited Oct 26 '19 at 05:18

4

Get the property info first, and then set the value on the property:

PropertyInfo propertyInfo = objName.GetType().GetProperty(propertyName);
propertyInfo.SetValue(objName, value, null);

edited Oct 26 '19 at 05:18

Adam

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answered Oct 19 '12 at 08:41

harriyott

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score 4 · Answer 4 · answered Oct 19 '12 at 08:43

You can use Type.InvokeMember to do this.

private void SetObjectProperty(string propertyName, string value, rel objName) 
{ 
    objName.GetType().InvokeMember(propertyName, 
        BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty, 
        Type.DefaultBinder, objName, value); 
}

score 2 · Answer 5 · answered Oct 19 '12 at 08:44

You can do it via reflection:

void SetObjectProperty(object theObject, string propertyName, object value)
{
  Type type=theObject.GetType();
  var property=type.GetProperty(propertyName);
  var setter=property.SetMethod();
  setter.Invoke(theObject, new ojbject[]{value});
}

NOTE: Error handling intentionally left out for the sake of readability.

C# dynamically set property

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