/// <summary>
/// Trys to take 2 expressions returned from FindIEnumerable and join them together. I.e. If we Split list.First() with FindIEnumerable, we can join it back together with newList.First()
/// </summary>
/// <param name="baseExp"></param>
/// <param name="nextExp"></param>
/// <returns></returns>
public static Expression CombineExpressions(Expression baseExp, Expression nextExp)
{
switch (nextExp.NodeType)
{
case ExpressionType.Call:
{
var mc = (MethodCallExpression)nextExp;
if (mc.Object == null)
{
var args = new List <Expression> {
baseExp
};
var newParam = Expression.Parameter(baseExp.Type.GetGenericArguments().First());
foreach (var item in mc.Arguments.Skip(1))
{
var lambda = (LambdaExpression)item;
var exp = new ParameterReplacer().Replace(lambda, lambda.Parameters.First(), newParam);
args.Add(exp);
}
var call = ExpressionUtil.MakeExpressionCall(new[] { typeof(Queryable), typeof(Enumerable) }, mc.Method.Name, baseExp.Type.GetGenericArguments().ToArray(), args.ToArray());
return(call);
}
return(Expression.Call(baseExp, mc.Method, mc.Arguments));
}
default: throw new EntityGraphQLCompilerException($"Could not join expressions '{baseExp.NodeType} and '{nextExp.NodeType}'");
}
}
public static Expression SelectDynamic(ParameterExpression currentContextParam, Expression baseExp, IEnumerable <IGraphQLNode> fieldExpressions, ISchemaProvider schemaProvider)
{
Type dynamicType;
var memberInit = CreateNewExpression(currentContextParam, fieldExpressions, schemaProvider, out dynamicType);
var selector = Expression.Lambda(memberInit, currentContextParam);
return(ExpressionUtil.MakeExpressionCall(new [] { typeof(Queryable), typeof(Enumerable) }, "Select", new Type[2] {
currentContextParam.Type, dynamicType
}, baseExp, selector));
}