# IExpressionReport interface

Namespace: [Grasshopper2.Data](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.data.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
public interface IExpressionReport
```

Collates all messages and errors that occur while applying an expression to a tree.

**Derived types:** [ExpressionReport](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.expressionreport.md)

## Properties

- [ErrorCount](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/errorcount.md): Gets the number of error messages in this report.
- [Errors](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/errors.md): Iterate over all error messages.
- [Failures](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/failures.md): Gets the number of times the expression threw exceptions.
- [NullsCreated](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/nullscreated.md): Gets the number of non-null items that were converted into nulls by the expression.
- [NullsRemoved](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/nullsremoved.md): Gets the number of null items that were converted into non-null items by the expression.
- [Successes](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/successes.md): Gets the number of times the expression was successfully applied.
- [WarningCount](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/warningcount.md): Gets the number of warning messages in this report.
- [Warnings](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/warnings.md): Iterate over all warning messages.

## Methods

- [Merge](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.iexpressionreport/merge.md): Merge data from another report.