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dotnet/Documentation/compatibility/aspnet-asp.net-validationcontext.membername-is-null-sometimes.md
2019-07-10 17:05:33 +00:00

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## ASP.NET ValidationContext.MemberName is not NULL when using custom DataAnnotations.ValidationAttribute
### Version Introduced
4.8
### Change Description
In .NET Framework 4.7.2 and earlier versions, when using a custom <xref:System.ComponentModel.DataAnnotations.ValidationAttribute?displayProperty=nameWithType>, the <xref:System.ComponentModel.DataAnnotations.ValidationContext.MemberName?displayProperty=nameWithType> property returns `null`. In .NET Framework 4.8, it returns the member name.
### Recommended Action
The default behavior of the <xref:System.ComponentModel.DataAnnotations.ValidationContext.MemberName?displayProperty=nameWithType> property remains the same. To retrieve a valid value from the `ValidationContext.MemberName` property, add the following setting to your app config file:
```xml
<configuration>
<appSettings>
...
<add key="aspnet:GetValidationMemberName" value="true"/>
...
</appSettings>
</configuration>
```
### Affected APIs
* `P:System.ComponentModel.DataAnnotations.ValidationContext.MemberName`
### Category
ASP.NET
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### 563497 <ASP.NET WebForms> ValidationContext.MemberName is NULL with custom DataAnnotations.ValidationAttribute
-->