属性调用PropertyInfo.SetValue后获取默认值

Question

I am using reflection to set a value of a property, but it is not working! this is because the default color is resetting after! That's is my code:

MapWindow.xaml:

<Window x:Class="MapRepresentation.MapWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MapWindow" SizeToContent="WidthAndHeight">
    <Grid Width="640" Height="739">
        <Path x:Name="akkar" Data="..." HorizontalAlignment="Right" Height="124.318" Margin="0,6.482,82.619,0" Stretch="Fill" Stroke="Red" VerticalAlignment="Top" Width="211.881" /> 
    </Grid>
</Window>

MapWindow.Xaml.cs:

public Brush AkkarColor  
{  
    get { return this.akkar.Fill; }
    set { this.akkar.Fill = value; }
}

public void ChangeColor()
{  
    Type type = GetType();
    object obj = Activator.CreateInstance(type);
    PropertyInfo pathInfo = type.GetProperty("AkkarColor");
    pathInfo.SetValue(obj, System.Windows.Media.Brushes.Red, null);
}

private void akkar_MouseEnter(object sender, MouseEventArgs e)
{  
    ChangeColor();
}

what is wrong ? why the color of the path Akkar is not changing?

Answer 1

It is because you are creating a new instance of the MapWindow . Pass this to SetValue .

public void ChangeColor()  
{  
   Type type = GetType();  
    PropertyInfo pathInfo = type.GetProperty("AkkarColor");  
    pathInfo.SetValue(this, System.Windows.Media.Brushes.Red, null);  
}  

Answer 2

You're creating a new instance of the current type, setting a property on it, and then ignoring the newly created object. I suspect you want to change the property on the current object, ie

// Remove the line declaring and initializing obj
pathInfo.SetValue(this, System.Windows.Media.Brushes.Red, null); 

Having said that, it's not at all clear why you're using reflection in the first place.