I'm writing a WPF applicating, in C#, using ArcObjects.
I have an ESRI.ArcGIS.Controls.AxMapControl on my form, and I'm trying to draw some graphics elements on top of it.
The map I'm developing with is a customer-provided mdf of the state of Georgia.
I'm trying an example I found here: How to interact with map elements.
public void AddTextElement(IMap map, double x, double y)
{
IGraphicsContainer graphicsContainer = map as IGraphicsContainer;
IElement element = new TextElementClass();
ITextElement textElement = element as ITextElement;
//Create a point as the shape of the element.
IPoint point = new PointClass();
point.X = x;
point.Y = y;
element.Geometry = point;
textElement.Text = "Hello World";
graphicsContainer.AddElement(element, 0);
//Flag the new text to invalidate.
IActiveView activeView = map as IActiveView;
activeView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
It took while to figure out how to project the lat/long of Atlanta to the coordinate system of the map, but I'm pretty sure that I've got it right. The x/y values I'm passing into AddTextElement() are clearly within the Atlanta area, according to the Location data I see when I use the Identify tool on the map.
But I'm not seeing the text. Everything seems to be working correctly, but I'm not seeing the text.
I can see a number of possibilities:
- The layer I'm adding the TextElement to isn't visible, or doesn't exist.
- I need to apply a spatial reference system to the point I'm setting as the TextElement's geometry
- The text is drawing fine, but there's something wrong with the font - it's invisibly small, or in a transparent color, etc.
Haven't a clue, which.
I was hoping there was something obvious I was missing.
===
As I've continued to play with this, since my original posting, I've discovered that the problem is the scaling - the text is showing up where it should, only unreadably small.
This is what Rich Wawrzonek had suggested.
If I set a TextSymbol class, with a specified Size, the size does apply, and I see me text larger or smaller. Unfortunately, the text still resizes as the map zooms in and out, and my trying to set ScaleText = false doesn't fix it.
My latest attempt:
public void AddTextElement(IMap map, double x, double y, string text)
{
var textElement = new TextElementClass
{
Geometry = new PointClass() { X = x, Y = y },
Text = text,
ScaleText = false,
Symbol = new TextSymbolClass {Size = 25000}
};
(map as IGraphicsContainer)?.AddElement(textElement, 0);
(map as IActiveView)?.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
I recognize that the above is organized very differently than the way is usually done with ESRI sample code. I find the way ESRI does it to be every difficult to read, but switch from one to another is pretty mechanical.
This is the same function, organized in a more traditional manner. The behavior should be identical, and I'm seeing exactly the same behavior - the text is drawn to a specified size, but scales as the map zooms.
public void AddTextElement(IMap map, double x, double y, string text)
{
IPoint point = new PointClass();
point.X = x;
point.Y = y;
ITextSymbol textSymbol = new TextSymbolClass();
textSymbol.Size = 25000;
var textElement = new TextElementClass();
textElement.Geometry = point;
textElement.Text = text;
textElement.ScaleText = false;
textElement.Symbol = textSymbol;
var iGraphicsContainer = map as IGraphicsContainer;
Debug.Assert(iGraphicsContainer != null, "iGraphicsContainer != null");
iGraphicsContainer.AddElement(textElement, 0);
var iActiveView = (map as IActiveView);
Debug.Assert(iActiveView != null, "iActiveView != null");
iActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
Any ideas as to why ScaleText is being ignored?
