public void Can_set_field_with_expression_tree_in_Net35()
{
// Shows how expression could look like:
Func <Holder, Holder> setHolderField = h => FieldAndPropSetter.SetField(h, ref h.Field, 111);
var holder = new Holder();
holder = setHolderField(holder);
Assert.AreEqual(111, holder.Field);
var holderType = typeof(Holder);
var field = holderType.GetField("Field");
var fieldSetterMethod =
typeof(FieldAndPropSetter).GetMethod("SetField")
.MakeGenericMethod(holderType, field.FieldType);
var holderParamExpr = Expression.Parameter(holderType, "h");
var fieldAccessExpr = Expression.Field(holderParamExpr, field);
// Result expression looks like: h => FieldAndPropSetter.SetField(h, ref h.Field, 222)
var setHolderFieldExpr = Expression.Lambda <Func <Holder, Holder> >(
Expression.Call(fieldSetterMethod, holderParamExpr, fieldAccessExpr, Expression.Constant(222)),
holderParamExpr);
var setHolderFieldGenerated = setHolderFieldExpr.Compile();
holder = setHolderFieldGenerated(holder);
Assert.AreEqual(222, holder.Field);
}
public void Can_set_property_with_expression_tree_in_Net35()
{
// Shows how expression could look like:
Func <Holder, Holder> setHolderProp = h => FieldAndPropSetter.SetProp(h, _ => _.Prop = "ABC");
var holder = new Holder();
holder = setHolderProp(holder);
Assert.AreEqual("ABC", holder.Prop);
var holderType = typeof(Holder);
var prop = holderType.GetProperty("Prop");
var propSet = prop.GetSetMethod();
var holderParamExpr = Expression.Parameter(holderType, "h");
var callSetPropExpr = Expression.Call(holderParamExpr, propSet, Expression.Constant("XXX"));
var setPropActionExpr = Expression.Lambda(callSetPropExpr, holderParamExpr);
var propSetterMethod = typeof(FieldAndPropSetter).GetMethod("SetProp").MakeGenericMethod(holderType);
// Result expression looks like: h => FieldAndPropSetter.SetProp(h, _ => _.Prop = "XXX")
var setHolderPropExpr = Expression.Lambda <Func <Holder, Holder> >(
Expression.Call(propSetterMethod, holderParamExpr, setPropActionExpr),
holderParamExpr);
var setHolderPropGenerated = setHolderPropExpr.Compile();
holder = setHolderPropGenerated(holder);
Assert.AreEqual("XXX", holder.Prop);
}
