Change ReadOnly attribute on property doesn't work

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I've tried to change a readonly attribute over reflection. Everything runs nice with the normal properties. But when I'm using a custom editor, it doesn't change the attribute. I've also tried to get an answer in this forum, but after one day nobody has looked on this topic, so I ask here again (and last time)

Here are the properties I want to change:

C#

[UIPathEditor.OfdParams("Video Files|*.wmv", "Choose Background Video")]
[Editor(typeof(UIPathEditor), typeof(UITypeEditor))]
[ReadOnly(false)]
[Description("The background video")]
[Category("Appearance")]
public string Video
{
    get { return _backgroundVideo; }
    set { _backgroundVideo = value; }
}

[ReadOnly(false)]
[Description("The volume of the video")]
[Category("Appearance")]
public int Volume
{
    get { return _volume; }
    set { if (value <= 100 && value >= 0)_volume = value;}
}

This is the code I use to do this:

C#

PropertyDescriptor property;
           ReadOnlyAttribute attribute;
           FieldInfo isReadOnly;

           property = TypeDescriptor.GetProperties(typeof(MenuProp))["Video"];
           attribute = (ReadOnlyAttribute)property.Attributes[typeof(ReadOnlyAttribute)];
           isReadOnly = attribute.GetType().GetField("isReadOnly", BindingFlags.NonPublic | BindingFlags.Instance);

           isReadOnly.SetValue(attribute, Video);

           property = TypeDescriptor.GetProperties(typeof(MenuProp))["Volume"];
           attribute = (ReadOnlyAttribute)property.Attributes[typeof(ReadOnlyAttribute)];
           isReadOnly = attribute.GetType().GetField("isReadOnly", BindingFlags.NonPublic | BindingFlags.Instance);

           isReadOnly.SetValue(attribute, Volume);

With the volume-property it runs fine. But on the Video property it has no effect...

I want to change the Attribute[ReadOnly(false)] because its for a property-grid where I want to edit those properties. And I want to switch between editable and non-editable depending on the choosen object.

Posted 9-Sep-11 21:41pm

PotensGladius

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Comments

OriginalGriff 10-Sep-11 3:46am

If nobody answered last time, there is probably a good reason: Nobody knows the answer. Reposting the same question is just rude, and unhelpful given that it is now a Saturday, and you are even less likely to get a response that you were yesterday...

Aoi Karasu 10-Sep-11 6:33am

isReadOnly.SetValue(attribute, Video); <-- does this even work? I cannot compile it. Shoudn't it be isReadOnly.SetValue(attribute, true); or isReadOnly.SetValue(attribute, false); ?

PotensGladius 14-Sep-11 13:27pm

Video is a boolean parameter value

3 solutions

Solution 1

The video property has an Editor defined on it, and that editor is responsible for the readonly checking, try removing it.

Posted 9-Sep-11 22:02pm

Mehdi Gholam

Comments

PotensGladius 14-Sep-11 13:28pm

I can't because I want a path browser for this property for the designer grid.

Solution 2

Hi,
Try to search in Google may be find it;

this code get it form google may be help u

------------------------

C#

class TestClass
{
    private bool isMyPropertyReadOnly;

    public bool IsMyPropertyReadOnly
    {
        get { return isMyPropertyReadOnly; }
        set { isMyPropertyReadOnly = value; }
    }

    private int myVar;

    public int MyProperty
    {
        get { return myVar; }

        set
        {
            if (isMyPropertyReadOnly)
            {
                throw new System.Exception("The MyProperty property is read-only.");
            }
            else
            {
                myVar = value;
            }
        }
    }
}

Posted 9-Sep-11 22:08pm

ayad0net

Comments

PotensGladius 14-Sep-11 13:29pm

You're good. I've searched in google about feeled 5 hours and found nothing.

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**Aoi Karasu** · Accepted Answer · 2011-09-10T00:44:00

This does not compile for me:

isReadOnly.SetValue(attribute, Video);

This does compile but gives you incorrect behavior:

isReadOnly.SetValue(attribute, Volume);

Try it like this:

public class MenuProp
{
    // ... class content ...

	public void ChangeReadOnlyTo(bool readOnly)
	{
		PropertyDescriptor property;
		ReadOnlyAttribute attribute;
		FieldInfo isReadOnly;

		property = TypeDescriptor.GetProperties(typeof(MenuProp))["Video"];
		attribute = (ReadOnlyAttribute)property.Attributes[typeof(ReadOnlyAttribute)];
		isReadOnly = attribute.GetType().GetField("isReadOnly", BindingFlags.NonPublic | BindingFlags.Instance);

        	// Here you set the attribute value to true or false
		isReadOnly.SetValue(attribute, readOnly);

		property = TypeDescriptor.GetProperties(typeof(MenuProp))["Volume"];
		attribute = (ReadOnlyAttribute)property.Attributes[typeof(ReadOnlyAttribute)];
		isReadOnly = attribute.GetType().GetField("isReadOnly", BindingFlags.NonPublic | BindingFlags.Instance);

		// Here you set the attribute value to true or false
		isReadOnly.SetValue(attribute, readOnly);
	}
}

Also make sure that UIPathEditor respects the value of the ReadOnlyAttribute.

Change ReadOnly attribute on property doesn't work

3 solutions

Solution 1

Solution 2

Solution 3

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