How to Resolve the "You can assign System.String, IImage, System.Drawing.Image" Error in Telerik Reporting

Environment

Property	Value
Product	Progress® Telerik® Reporting
Version	17.2.23.1010+
Graphics Engine	Skia

Description

I have a CLR report definition created with the Visual Studio Report Designer for the .NET Framework.

I received an error message You can assign System.String, IImage, System.Drawing.Image (for GDI rendering), or SKBitmap (for Skia rendering) instances only when using Telerik Reporting with the Skia graphics engine.

Solution

When you embed images in reports in the Visual Studio Report Designer, they get added as resources in the resx file of the report definition.

If you open the resource file with a text editor like Notepad++, the corresponding asset looks like the next snippet that represents a System.Drawing.Bitmap object:

XML

<assembly alias="System.Drawing" name="System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
<data name="pictureBox2.Value" type="System.Drawing.Bitmap, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
	<value>
		iVBORw0KGgoAAAANSUhEUgAAAIAAAACACAYAAADDPmHLAAAAAXNSR0I....
	</value>
</data>

Skia does not support the types from the GDI namespace System.Drawing. To resolve this error, you need to change the type of the above image to a type that is valid for both Skia and System.Drawing (GDI) graphic engines.

Follow these steps to fix the error:

1. Open the RESX file that contains the code referencing the image.

2. Locate the code that references the image as a Bitmap instance:

   XML

   <assembly alias="System.Drawing" name="System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
   <data name="{pictureBoxNameHere}.Value" type="System.Drawing.Bitmap, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
   	<value>
   		{the value of the image base64 string here}
   	</value>
   </data>

3. Replace the code referencing the image with a pure base64 string:

   XML

   <data name="{pictureBoxNameHere}.Value" xml:space="preserve">
   	<value>
   		{the value of the image base64 string here}
   	</value>
   </data>

The result for the sample image above would be:

XML

<data name="pictureBox2.Value" xml:space="preserve">
	<value>
		iVBORw0KGgoAAAANSUhEUgAAAIAAAACACAYAAADDPmHLAAAAAXNSR0I....
	</value>
</data>

Note

If you assign the PictureBox value with code, you can also cast the Bitmap to Telerik.Drawing.ImageBase or byte[] before assigning it to the report item.