public static Builders.FieldBuilder <IDictionary <string, object>, TProperty> EfField <TDbContext, TSource, TProperty>(this IEfGraph <TDbContext, TSource> graph, Expression <Func <TSource, TProperty> > expression, bool nullable = false, Type graphType = null) where TDbContext : DbContext where TSource : class
{
if (graph == null)
{
throw new ArgumentNullException(nameof(graph));
}
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
//obtain the name
string name;
try
{
name = expression.NameOf();
}
catch
{
throw new ArgumentException(
$"Cannot infer a Field name from the expression: '{expression.Body.ToString()}' " +
$"on parent GraphQL type: '{graph.Name ?? graph.GetType().Name}'.");
}
return(EfField(graph, name, expression, nullable, graphType));
}
private static Builders.FieldBuilder <IDictionary <string, object>, TReturn> EfFieldFromContext <TDbContext, TSource, TReturn>(this IEfGraph <TDbContext, TSource> graph, string name, Func <ResolveEfFieldContext <TDbContext, TSource>, LambdaExpression> expression, bool nullable = false, Type graphType = null) where TDbContext : DbContext where TSource : class
{
//obtain the type
try
{
if (graphType == null)
{
graphType = typeof(TReturn).GetGraphTypeFromType(nullable);
}
}
catch (ArgumentOutOfRangeException exp)
{
throw new ArgumentException(
$"The GraphQL type for Field: '{name}' on parent type: '{graph.Name ?? graph.GetType().Name}' could not be derived implicitly. \n",
exp
);
}
var builder = FieldBuilder.Create <IDictionary <string, object>, TReturn>(graphType)
.Name(name)
.Resolve(EfGraphResolver)
//.Description(expression.DescriptionOf())
//.DeprecationReason(expression.DeprecationReasonOf())
//.DefaultValue(expression.DefaultValueOf())
;
builder.FieldType.SetExpressionMetadata <TDbContext, TSource>(expression);
graph.AddField(builder.FieldType);
return(builder);
}