@H_301_1@这可能适用于其他地方,但在WinForms中,当我使用绑定时,我发现许多方法都希望将属性的名称绑定到.就像是:
class Person { public String Name { get { ... } set { ... } } public int Age { get { ... } set { ... } } } class PersonView { void Bind(Person p) { nameControl.Bind(p,"Name"); ageControl.Bind(p,"Age"); } }
我一直遇到的一个大问题是“Name”和“Age”被指定为字符串.这意味着如果有人重命名Person的一个属性,编译器就无济于事.代码编译正常,但绑定将被破坏.
我错过了解决这个问题的标准方法吗?感觉我需要一些关键字,也许叫做stringof来匹配现有的typeof.你可以使用它:
ageControl.Bind(p,stringof(p.Age).Name);
stringof可以返回一些具有获取完整路径,路径的一部分或字符串的属性的类,以便您可以自己解析它.
这样的事情已经可以吗?
解决方法
您可以使用表达式来获取编译器检查的绑定.
例如,在当前的一个项目中,我们设置了这样的绑定:
例如,在当前的一个项目中,我们设置了这样的绑定:
DataBinder .BindToObject(this) .ObjectProperty(c => c.IsReadOnly) .Control(nameTextBox,n => n.ReadOnly) .Control(addressControl,n => n.ReadOnly)
public static class DataBinder { public static DataBinderBindingSourceContext<TDataSource> BindToObject<TDataSource>(TDataSource dataSource) { return new DataBinderBindingSourceContext<TDataSource>(dataSource); } } public class DataBinderBindingSourceContext<TDataSource> { public readonly object DataSource; public DataBinderBindingSourceContext(object dataSource) { DataSource = dataSource; } public DataBinderControlContext<TDataSource,TProperty> ObjectProperty<TProperty>(Expression<Func<TDataSource,TProperty>> property) { return new DataBinderControlContext<TDataSource,TProperty>(this,property); } } public class DataBinderControlContext<TDataSource,TProperty> { readonly DataBinderBindingSourceContext<TDataSource> BindingSourceContext; readonly string ObjectProperty; public DataBinderControlContext ( DataBinderBindingSourceContext<TDataSource> bindingSourceContext,Expression<Func<TDataSource,TProperty>> objectProperty ) { BindingSourceContext = RequireArg.NotNull(bindingSourceContext); ObjectProperty = ExpressionHelper.GetPropertyName(objectProperty); } public DataBinderControlContext<TDataSource,TProperty> Control<TControl>(TControl control,Expression<Func<TControl,TProperty>> property) where TControl : Control { var controlPropertyName = ExpressionHelper.GetPropertyName(property); control.DataBindings.Add(controlPropertyName,BindingSourceContext.DataSource,ObjectProperty,true); return this; } } public static class ExpressionHelper { public static string GetPropertyName<TResult>(Expression<Func<TResult>> property) { return GetMemberNames(((LambdaExpression)property).Body).Skip(1).Join("."); } public static string GetPropertyName<T,TResult>(Expression<Func<T,TResult>> property) { return GetMemberNames(((LambdaExpression)property).Body).Join("."); } static IEnumerable<string> GetMemberNames(Expression expression) { if (expression is ConstantExpression || expression is ParameterExpression) yield break; var memberExpression = (MemberExpression)expression; foreach (var memberName in GetMemberNames(memberExpression.Expression)) yield return memberName; yield return memberExpression.Member.Name; } } public static class StringExtentions { public static string Join(this IEnumerable<string> values,string separator) { if (values == null) return null; return string.Join(separator,values.ToArray()); } }