/// <summary>
/// Order.Qty > 100 and Order.Customer = "Zhang San"
/// 100>Order.Price
/// </summary>
/// <returns></returns>
public ExpressionContext On()
{
var orderParam = new ParameterExpression()
{
Name = "Order",
Alia = "Dest",
Type = typeof(Order)
};
var exp = orderParam.Member("Qty")
.GT(new ConstantExpression(100))
.And(orderParam.Member("Customer")
.Equal(new ConstantExpression("Zhang San")));
return new ExpressionContext
{
Parameters = new List<ParameterExpression> { orderParam },
Expression = exp,
};
}
/// <summary>
/// Src join Dest on Src.Id = Dest.SourceOrder
/// </summary>
/// <returns></returns>
public Expression Join()
{
var fromParam = new ParameterExpression()
{
Name = "Order",
Alia = "Src",
Type = typeof(Order)
};
var destParam = new ParameterExpression()
{
Name = "Order",
Alia = "Dest",
Type = typeof(Order)
};
var joinOnCriteria = fromParam.Member("Id")
.Equal(destParam.Member("SourceOrder"));
var join = fromParam.Join(destParam, joinOnCriteria);
return join;
}
