AddContract(IAdviser<IParameter>, string, ContractDirection, object?, object?)
Adds a contract to a parameter. Contracts validate or normalize parameter values at different points in the data flow, typically used for precondition checks (input parameters) or postcondition checks (output parameters and return values). Use the With<TNewDeclaration>(TNewDeclaration) method to add the contract to a different parameter than the current one.
Declaration
public static IAddContractAdviceResult<IParameter> AddContract(this IAdviser<IParameter> adviser, string template, ContractDirection direction = ContractDirection.Default, object? args = null, object? tags = null)Parameters
| Type | Name | Description |
|---|---|---|
| IAdviser<IParameter> | adviser | An adviser for a parameter. |
| string | template | The name of the template method. This method must have a single run-time parameter named |
| ContractDirection | direction | Direction of the data flow to which the contract should apply. Use Input for preconditions, Output for postconditions, or Default to select automatically based on parameter type. See ContractDirection for details. |
| object | args | An object (typically of anonymous type) whose properties map to parameters or type parameters of the template. |
| object | tags | An optional object (typically of anonymous type) passed to the template and accessible via |
Returns
| Type | Description |
|---|---|
| IAddContractAdviceResult<IParameter> | An IAddContractAdviceResult<T> exposing the added contract. |
Remarks
Template Access: Within the template, use meta.Target.Expression for unified access to the target as an IExpression,
meta.Target.Parameter for parameter-specific access, and meta.Target.ContractDirection to determine whether you're validating input or output.
Performance Note: When possible, provide all contracts to the same method from a single aspect. This approach yields better compile-time performance than using several separate aspects.
Ready-Made Contracts: Consider using the Metalama.Patterns.Contracts package, which provides ready-made contract attributes for common validation scenarios
(nullability, strings, numeric ranges, enums, collections). See Metalama.Patterns.ContractsMetalama.Patterns.Contracts for details.
See Also
AddContract(IAdviser<IFieldOrPropertyOrIndexer>, string, ContractDirection, object?, object?)
Adds a contract to a field, property or indexer. Contracts validate or normalize values, typically used to validate assigned values (setters) or returned values (getters). Fields with contracts are automatically transformed into properties. Use the With<TNewDeclaration>(TNewDeclaration) method to add the contract to a different field, property or indexer than the current one.
Declaration
public static IAddContractAdviceResult<IFieldOrPropertyOrIndexer> AddContract(this IAdviser<IFieldOrPropertyOrIndexer> adviser, string template, ContractDirection direction = ContractDirection.Default, object? args = null, object? tags = null)Parameters
| Type | Name | Description |
|---|---|---|
| IAdviser<IFieldOrPropertyOrIndexer> | adviser | An adviser for a field, property or indexer. |
| string | template | The name of the template method. This method must have a single run-time parameter named |
| ContractDirection | direction | Direction of the data flow to which the contract should apply. Use Input to validate values being assigned (setter), Output to validate values being retrieved (getter), or Default to select automatically. See ContractDirection for details. |
| object | args | An object (typically of anonymous type) whose properties map to parameters or type parameters of the template. |
| object | tags | An optional object (typically of anonymous type) passed to the template and accessible via |
Returns
| Type | Description |
|---|---|
| IAddContractAdviceResult<IFieldOrPropertyOrIndexer> | An IAddContractAdviceResult<T> exposing the added contract. |
Remarks
Template Access: Within the template, use meta.Target.Expression for unified access to the target as an IExpression,
meta.Target.FieldOrProperty for field/property-specific access, and meta.Target.ContractDirection to determine whether you're validating input or output.
Performance Note: When possible, provide all contracts to the same method from a single aspect. This approach yields better compile-time performance than using several separate aspects.
Ready-Made Contracts: Consider using the Metalama.Patterns.Contracts package, which provides ready-made contract attributes for common validation scenarios
(nullability, strings, numeric ranges, enums, collections). See Metalama.Patterns.ContractsMetalama.Patterns.Contracts for details.