Result as C# Object

• The overloaded methods QueryObject in interface JsonQL.Query.IQueryManager and similarly named overloaded extension methods with generic parameter QueryObject<TQueryObject> in JsonQL.Query.QueryManagerExtensions can be used to to query one or more JSON files using a JsonQL query expressions.

Note

• The extension methods with generic parameter TQueryObject are easier to use. The methods in JsonQL.Query.IQueryManager might be easier to use with reflection.

• Moving forward the extension methods will be discussed.

• The result of a query is stored in an instance of JsonQL.Query.IObjectQueryResult<TQueryObject> a C# interface, where TQueryObject is the value of generic type argument passed to one of overloaded methods QueryObject<TQueryObject>.

• Interface JsonQL.Query.IObjectQueryResult<TQueryObject> has a property ErrorsAndWarnings of type JsonQL.Query.IQueryResultErrorsAndWarnings that stores data about query execution errors, if any.

  Note

  The errors might contain both errors in queried files, if queried files use JsonQL expressions (or are not well formed), as well as errors in query itself, or errors encountered when converting result JSON to a C# object.

• Interface JsonQL.Query.IObjectQueryResult<TQueryObject> has a property Value of generic type TQueryObject which contains de-serialized query result.

• The type parameter TQueryObject specified in overloaded query methods TQueryObject in JsonQL.Query.QueryManagerExtensions specifies the type to which the query result should be converted.

  • TQueryObject can be any class (value or reference type) including collection types.

  • Both interface and implementation class can be used for TQueryObject.

  • Nullable syntax ? can be specified with type argument value for TQueryObject: this includes also using nullable syntax for collection item types, if return type is a collection.

  • If collection type is used for type parameter TQueryObject in a call to IJsonQL.Query.QueryManager.QueryObject<TQueryObject> method, the collection item parameters can be interfaces or classes as well (both value or reference type).

• One ore more JSON files can be specified as parameters to be used when looking up JSON values referenced by JsonQL expressions.

• If many JSON files are specified the following rules and techniques are used: - Parent/child relationships between JSON files is maintained and parent JSON files are evaluated before child JSON files are evaluated. - Lookup of JSON values specified in JsonQL expressions starts in JSON containing the expression first, and then in parent JSON files.

Note

For more examples look at examples at these links:

• Successful query examples in JsonQL.Demos project

• Failed query examples in JsonQL.Demos project

• Examples in JsonQL.Tests project

• Examples
  • Example of querying for a C# reference type object
  • Example of querying for value type value
  • Example of converting root JSON with JsonQL expressions to a C# object
• Empty Query to Convert Json to Object Without Filtering
• Error Details
  • Examples
    • Compilation error
    • Conversion error
• Type Binding
  • Examples
    • Convert to Classes
    • Convert to Classes Interfaces
    • Replace Interface Implementation
• Nullable Value Support
  • Nullable Syntax in Query Result Type
    • Examples
      • Result as Value Type
      • Result as Reference Type
      • Result as List of Value Type Items
      • Result as Arrays of Reference Type Items
      • Result as List of Arrays of Value Type Items
      • Result as List of Lists of Reference Type Items
  • Nullable Syntax in Queried Object Properties
• Conversion Settings
  • Setting ConversionErrorTypeConfigurations
    • Report Errors as Warnings Example
    • Ignore Errors Example
    • Report Errors Example
  • Setting FailOnFirstError
  • Setting JsonPropertyFormat
  • Setting TryMapJsonConversionType
    • Example
• Sample Files
  • Countries.json
  • Companies.json
  • Parameters.json
  • FilteredCompanies.json