wpf-nullreferenceexception-in-exception-handling-code-from-imagesourceconverter_convertfrom.md

NullReferenceException in exception handling code from ImageSourceConverter.ConvertFrom

Scope

Edge

Version Introduced

4.7

Source Analyzer Status

NotPlanned

Change Description

An error in the exception handling code for xref:System.Windows.Media.ImageSourceConverter.ConvertFrom(System.ComponentModel.ITypeDescriptorContext,System.Globalization.CultureInfo,System.Object) caused an incorrect xref:System.NullReferenceException?displayProperty=name to be thrown instead of the intended exception ( xref:System.IO.DirectoryNotFoundException?displayProperty=name or xref:System.IO.FileNotFoundException?displayProperty=name). This change corrects that error so that the method now throws the right exception.

By default all applications targeting .NET Framework 4.6.2 and earlier continue to throw xref:System.NullReferenceException?displayProperty=name for compatibility. Developers targeting .NET Framework 4.7 and above should see the right exceptions.

• Quirked
• Build-time break

Recommended Action

Developers who wish to revert to getting xref:System.NullReferenceException?displayProperty=name when targeting .NET Framework 4.7 or later can add/merge the following to their application's App.config file:

<configuration>
    <runtime>
        <AppContextSwitchOverrides value="Switch.System.Windows.Media.ImageSourceConverter.OverrideExceptionWithNullReferenceException=true"/>
    </runtime>
</configuration>

Affected APIs

• M:System.Windows.Media.ImageSourceConverter.ConvertFrom(System.ComponentModel.ITypeDescriptorContext,System.Globalization.CultureInfo,System.Object)

Category

Windows Presentation Foundation (WPF)