Working with cursors on WPF graph

[b!tmaster]

Hello friends,

I have been working on how to use cursors with a WPF graph in an MVVM application but I am having trouble accomplishing a few things. I have created a cursor on my graph with the following statement...

<ni:Cursor SnapToData="False" InteractionMode="Mouse" AllowablePlots="Single" Plot="{Binding ElementName = channelPlot}" HorizontalCrosshairLength="0" TargetSize="0,0"/>

I set the HorizontalCrosshairLength to 0 because I am only interested in the vertical crosshair. I set the TargetSize to 0,0 because I do not need anything to display at the intersection of the crosshairs.

With that being said I have the following questions...

1. At the intersection of the vertical & horizontal crosshairs, the X and Y value of the intersection are displayed, how can I hide these X and Y values?
2. How can I set the default position of my vertical crosshair?
3. How can I change the color of my cursor?

Thanks!

[phansen · Accepted solution]

1) You can use the ValueVisibility property to hide the display of the value.

2) By default, a Cursor takes a position in the center of the plot area at the time it is loaded into a graph. To change this position, you will need to call one of the Set*Position methods, such as SetRelativePosition or SetDataPosition.

3) Since you are hiding the target, you can use the CrosshairBrush property to change the color of your cursor.

[b!tmaster]

phasen,

1. I set the ValueVisibility property to collapsed and this removed the value display.
2. Unfortunately I think I am going to have to break my MVVM pattern to use the Set*Position methods in my code behind but regardless, thanks for pointing out which methods I need to move cursor position.
3. I am now able to change the color of my cursor using the mentioned property.

Thanks for your help!

[phansen]

For the Set*Position methods, you could also optionally create an attached property to do a one-time set using XAML, if that makes more sense for your scenario.

[b!tmaster]

It sounds like that may make more sense for my scenario, I am unaware of how to implement an attached property though so I will do some research.

[phansen]

From a quick search, this article might be a helpful reference: Introduction to Attached Behaviors in WPF.

[b!tmaster]

Thanks for the reference, I realized that I am going to have to be able to set the position of the cursors repeatedly (not just one time) so I am just going to use the code behind approach.