Fix: Crash viewer when entering text.

- Catch exceptions in event handler.

Samples/SVGViewer/SvgViewer.cs

@@ -21,6 +21,8 @@ namespace SVGViewer
         }
 
         private void open_Click(object sender, EventArgs e)
+        {
+            try
             {
                 if (openSvgFile.ShowDialog() == DialogResult.OK)
                 {
@@ -28,15 +30,25 @@ namespace SVGViewer
                     RenderSvg(svgDoc);
                 }
             }
+            catch
+            {
+            }
+        }
 
         private void textBox1_TextChanged(object sender, EventArgs e)
         {
-        	using(var s = new MemoryStream(Encoding.UTF8.GetBytes(textBox1.Text)))
+            try
+            {
+                using (var s = new MemoryStream(Encoding.UTF8.GetBytes(textBox1.Text)))
                 {
                     SvgDocument svgDoc = SvgDocument.Open<SvgDocument>(s, null);
                     RenderSvg(svgDoc);
                 }
             }
+            catch
+            {
+            }
+        }
 
         private void RenderSvg(SvgDocument svgDoc)
         {