我们遇到了一个问题,其中:
- 在一个 MDI 工作区中,我们有两个实例绑定到两个不同的对象模型。
- 这些对象模型已覆盖其
.Equals
和.GetHashCode
方法以被认为是相等的。 - 在窗口2上调用
.EndCurrentEdit()
会触发窗口1的绑定更新。 - 两个窗口都设置为使用单独的
BindingContext
。
我们已经发现这个问题与调用以下内容有关:
((PropertyManager)ctrl.BindingContext[dataSource]).EndCurrentEdit();
如果我们把它改成。((PropertyManager)ctrl.BindingContext[dataSource, dataMember]).EndCurrentEdit();
如果我们删除.Equals和.GetHashCode的重写,这个方法也可以正确运行,即两个对象模型不再被视为相等。
这对我来说没有意义,因为窗口是相同的,所以dataMember
属性也应该是相同的。
从此链接中,我认为这些调用的定义如下:
public BindingManagerBase this[object dataSource] {
get {
return this[dataSource, ""];
}
}
public BindingManagerBase this[object dataSource, string dataMember] {
get {
return EnsureListManager(dataSource, dataMember);
}
internal BindingManagerBase EnsureListManager(object dataSource, string dataMember) {
BindingManagerBase bindingManagerBase = null;
if (dataMember == null)
dataMember = "";
// Check whether data source wants to provide its own binding managers
// (but fall through to old logic if it fails to provide us with one)
//
if (dataSource is ICurrencyManagerProvider) {
bindingManagerBase = (dataSource as ICurrencyManagerProvider).GetRelatedCurrencyManager(dataMember);
if (bindingManagerBase != null) {
return bindingManagerBase;
}
}
// Check for previously created binding manager
//
HashKey key = GetKey(dataSource, dataMember);
WeakReference wRef;
wRef = listManagers[key] as WeakReference;
if (wRef != null)
bindingManagerBase = (BindingManagerBase) wRef.Target;
if (bindingManagerBase != null) {
return bindingManagerBase;
}
if (dataMember.Length == 0) {
// No data member specified, so create binding manager directly on the data source
//
if (dataSource is IList || dataSource is IListSource) {
// IListSource so we can bind the dataGrid to a table and a dataSet
bindingManagerBase = new CurrencyManager(dataSource);
}
else {
// Otherwise assume simple property binding
bindingManagerBase = new PropertyManager(dataSource);
}
}
else {
// Data member specified, so get data source's binding manager, and hook a 'related' binding manager to it
//
int lastDot = dataMember.LastIndexOf(".");
string dataPath = (lastDot == -1) ? "" : dataMember.Substring(0, lastDot);
string dataField = dataMember.Substring(lastDot + 1);
BindingManagerBase formerManager = EnsureListManager(dataSource, dataPath);
PropertyDescriptor prop = formerManager.GetItemProperties().Find(dataField, true);
if (prop == null)
throw new ArgumentException(SR.GetString(SR.RelatedListManagerChild, dataField));
if (typeof(IList).IsAssignableFrom(prop.PropertyType))
bindingManagerBase = new RelatedCurrencyManager(formerManager, dataField);
else
bindingManagerBase = new RelatedPropertyManager(formerManager, dataField);
}
我的dataSource
并不是一个ICurrencyManagerProvider
这两个调用有什么区别,为什么仅通过dataSource
访问PropertyManager
会导致绑定到另一个具有独立BindingContext
的窗口的数据更新?