![]() ![]() The IMvxValueConverter interface provides: Value Converters in MvvmCross are used to provide mappings to/from logical values in the view models and presented values in the user interface.Annke Rtsp pectpecarupt1987 JanuAnnke Rtsp a Convert method - for changing ViewModel values into View values.a ConvertBack method - for changing View values into ViewModel values. ![]() Public interface IMvxValueConverter įinally, ValueConverters can also be registered using a technique called “ValueConverter holders”. ![]() This technique uses Reflection against individual Types which then hold ValueConverters in public instance or static fields. Preventing the ValueConverter Reflection Sweeps in iOS and Droid This technique was common in earlier MvvmCross versions, but is not recommended within v3 - it’s kept only for backwards compatibility. The ValueConverter sweeps do use a small amount of Reflection and so can add a very small amount of lag to application start time. If you’d prefer to minimize this small startup lag in your application, then you can, of course, disable the sweeps and can use direct registration instead. To do this, override the FillValueConverters method in your Setup class, do not call the base class method and instead use just register your own value converters - e.g.WPF excels at creating great looking applications. One of the ways you can make your application look great is to add some shapes like circles, triangles and rectangles. However, the shapes in WPF do not allow you to add text (or any content) within the shape, as shapes are not containers. ![]() In a WPF application I am building right now, I have a need to create different shapes and center text within those shapes. The shapes I need are rectangles, circles, ellipses and triangles. The problem is WPF shapes are not containers so you cannot add any text inside of them, but WPF is flexible enough that there are often several ways to work around this. In this article, I will show you a few different methods of centering text in each of these shapes. If you wish to put text into an ellipse or a circle, you can simulate this using a Border control and play with the Width, Padding and CornerRadius properties of the Border control. I used the code snippet below to draw text within an ellipse as shown in Figure 1. Figure 1: Use a Border control to simulate an ellipse. You can set the width and height of the Border control to create a circle as well. The XAML in the next snippet creates a circle with text in the middle, as shown in Figure 2. Figure 2: Use a Border control to simulate a circle. To create a triangle shape in WPF you use a Polygon control. If you remember your high school math, a Polygon is a series of connected lines that have the same start and end point. The XAML below creates a triangle however, there is no text in it because a Polygon is not a container. To add text like that shown in Figure 3, you need to use the Polygon control as the background of a TextBlock control. The XAML shown in Listing 1 is used to create Figure 3. Figure 3: Use a Visual Brush to put text in a triangle. First, you use the VisualBrush object of the Background of the TextBlock object to give you a place to put the Polygon control. Second, depending on the text that you fill into the TextBlock control, and the width and height of the TextBlock control, you will need to play with the Padding property to align the text to the correct location. Take the above XAML and put it in a new window and then adjust the height, width and text values. You will see that you need to adjust the Padding property to make the text fall into the correct location within the Polygon. Listing 2 shows another example of a Visual Brush, this time using an Ellipse control. Figure 4 shows the results of the XAML in Listing 2. Figure 4: Use a Visual Brush to put text in an ellipse. Notice the Padding attribute is different than when using the Polygon control. ![]()
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