我有一个绑定到绑定源的 DataGridView，该绑定源绑定到 List<T>。用户单击进入带有文本框等的表单的行。文本框是数据绑定的，如下所示：
if (txtID.DataBindings.Count == 0)
txtID.DataBindings.Add("Text", bindingSource, "Title");
我希望能够检测用户在单击关闭按钮时是否修改了控件中的任何数据，因此我可以提示他们说“您有未保存的工作。您要保存吗？”
如何在绑定源上检测到这一点？
更新：我发现我可以做bindingSource.EndEdit()，它将更改推送到我在列表中的项目。在我的项目中，我可以说如果 Dirty 抛出一个消息框，但如果他们单击“否”来保存信息，则 CancelEdit 不起作用。
【问题讨论】：
标签： c# winforms data-binding ado.net subsonic
如果列表中的对象支持INotifyPropertyChanged 事件，并且您将List<T> 替换为BindingList<T>，则可以订阅BindingList 的ListChanged 事件以了解用户所做的任何更改。
【讨论】：
如果您绑定到 DataSet，那么您很幸运：它有一个 HasChanges 属性。您可以通过在数据集上调用 GetChanges 来获取实际更改。这将返回一个包含所有更改行的副本的新数据集
【讨论】：
我现在做了这个功能。你可以像这样使用：
if (changedOrNew(myBindingSource)){
// Do something!
}
public bool changedOrNew(BindingSource bs){
EntityObject obj = (EntityObject)bs.Current;
if (obj==null)
return false;
return (obj.EntityState == EntityState.Detached ||
obj.EntityState == EntityState.Added ||
obj.EntityState == EntityState.Modified);
}
【讨论】：
在尝试了不同的事情后，我最终得到了这段代码：
private MyClass currentItem = null;
private bool itemDirty = false; // can be used for "do you want to save?"
private void bindingSource_CurrentChanged(object sender, EventArgs e)
{
var handler = new PropertyChangedEventHandler((s, e2) => itemDirty = true);
var crnt = currentItem as INotifyPropertyChanged;
if(crnt != null) crnt.PropertyChanged -= handler;
currentItem = (MyClass)bindingSource.Current;
crnt = currentItem as INotifyPropertyChanged;
if(crnt != null) crnt.PropertyChanged += handler;
itemDirty = false;
}
虽然我在 Windows 窗体的实例字段中保存了很多状态信息，但它对我来说很好用。但是，玩弄CurrentChanged 和CurrentItemChanged 并没有帮助我。
【讨论】：
更简单的方法是订阅 BindingSource 的 ListChanged 事件并根据事件类型设置 IsDirty 标志。
categoryBindingSource.ListChanged +=
new System.ComponentModel.ListChangedEventHandler(categoryBindingSource_ListChanged);
并在事件方法中设置 IsDirty = true...
void customerAccountBindingSource_ListChanged(object sender, system.ComponentModel.ListChangedEventArgs e)
{
if (e.ListChangedType == System.ComponentModel.ListChangedType.ItemChanged)
_isDirty = true;
}
这里需要注意的是，它无法检测到修改后的值何时仍与原始值相同。 Memberwise.Clone 如果需要该级别的准确性，可以另外使用。
【讨论】：
我设置了一个相当简单的机制，如下：
如果有人感兴趣，我可以分享来源。
【讨论】：
如果您的绑定源使用数据表，您可以这样做：
public bool HasChanges()
{
bool Result = false;
myBindingSource.EndEdit();
Result = ((DataTable)myBindingSource.DataSource).GetChanges(DataRowState.Modified) != null;
return Result;
}
【讨论】：
我知道这是一篇旧帖子，但这里有一个带有 IsDirtyFlag 的 Extended BindingSource - 你可以随意调整它 - 我几年前从网上某处的另一个帖子中提取了这段代码 - 我认为它做了一些非常小的改动最初是在 VB 中 - 我转换为 C# ..
using System.ComponentModel.Design;
using System.Windows.Forms;
using System.ComponentModel;
using System.Data;
using System;
public class BindingSourceExIsDirty : System.Windows.Forms.BindingSource, INotifyPropertyChanged
{
#region "DECLARATIONS AND PROPERTIES"
private string _displayMember;
private DataTable _dataTable;
private DataSet _dataSet;
private BindingSource _parentBindingSource;
private System.Windows.Forms.Form _form;
private System.Windows.Forms.Control _usercontrol;
private bool _isCurrentDirtyFlag = false;
public bool IsCurrentDirty {
get { return _isCurrentDirtyFlag; }
set {
if (_isCurrentDirtyFlag != value) {
_isCurrentDirtyFlag = value;
this.OnPropertyChanged(value.ToString());
//call the event when flag is set
if (value == true) {
OnCurrentIsDirty(new EventArgs());
}
}
}
}
private string _objectSource;
public string ObjectSource {
get { return _objectSource; }
set {
_objectSource = value;
this.OnPropertyChanged(value);
}
}
private bool _autoSaveFlag;
public bool AutoSave {
get { return _autoSaveFlag; }
set {
_autoSaveFlag = value;
this.OnPropertyChanged(value.ToString());
}
}
#endregion
#region "EVENTS"
//Current Is Dirty Event
public event CurrentIsDirtyEventHandler CurrentIsDirty;
// Delegate declaration.
public delegate void CurrentIsDirtyEventHandler(object sender, EventArgs e);
protected virtual void OnCurrentIsDirty(EventArgs e)
{
if (CurrentIsDirty != null) {
CurrentIsDirty(this, e);
}
}
//PropertyChanged Event
// public event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged;
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string info)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(info));
}
}
#endregion
#region "METHODS"
private void _BindingComplete(System.Object sender, System.Windows.Forms.BindingCompleteEventArgs e)
{
if (e.BindingCompleteContext == BindingCompleteContext.DataSourceUpdate) {
if (e.BindingCompleteState == BindingCompleteState.Success & !e.Binding.Control.BindingContext.IsReadOnly) {
//Make sure the data source value is refreshed (fixes problem mousing off control)
e.Binding.ReadValue();
//if not focused then not a user edit.
if (!e.Binding.Control.Focused)
return;
//check for the lookup type of combobox that changes position instead of value
if (e.Binding.Control as ComboBox != null) {
//if the combo box has the same data member table as the binding source, ignore it
if (((ComboBox)e.Binding.Control).DataSource != null) {
if (((ComboBox)e.Binding.Control).DataSource as BindingSource != null) {
if (((BindingSource)((ComboBox)e.Binding.Control).DataSource).DataMember == (this.DataMember)) {
return;
}
}
}
}
IsCurrentDirty = true;
//set the dirty flag because data was changed
}
}
}
private void _DataSourceChanged(System.Object sender, System.EventArgs e)
{
_parentBindingSource = null;
if (this.DataSource == null) {
_dataSet = null;
} else {
//get a reference to the dataset
BindingSource bsTest = this;
Type dsType = bsTest.DataSource.GetType();
//try to cast the data source as a binding source
while ((bsTest.DataSource as BindingSource != null)) {
//set the parent binding source reference
if (_parentBindingSource == null)
_parentBindingSource = bsTest;
//if cast was successful, walk up the chain until dataset is reached
bsTest = (BindingSource)bsTest.DataSource;
}
//since it is no longer a binding source, it must be a dataset or something else
if (bsTest.DataSource as DataSet == null) {
//Cast as dataset did not work
if (dsType.IsClass == false) {
throw new ApplicationException("Invalid Binding Source ");
} else {
_dataSet = null;
}
} else {
_dataSet = (DataSet)bsTest.DataSource;
}
//is there a data member - find the datatable
if (!string.IsNullOrEmpty(this.DataMember)) {
_DataMemberChanged(sender, e);
}
//CType(value.GetService(GetType(IDesignerHost)), IDesignerHost)
if (_form == null)
GetFormInstance();
if (_usercontrol == null)
GetUserControlInstance();
}
}
private void _DataMemberChanged(System.Object sender, System.EventArgs e)
{
if (string.IsNullOrEmpty(this.DataMember) | _dataSet == null) {
_dataTable = null;
} else {
//check to see if the Data Member is the name of a table in the dataset
if (_dataSet.Tables(this.DataMember) == null) {
//it must be a relationship instead of a table
System.Data.DataRelation rel = _dataSet.Relations(this.DataMember);
if ((rel != null)) {
_dataTable = rel.ChildTable;
} else {
throw new ApplicationException("Invalid Data Member");
}
} else {
_dataTable = _dataSet.Tables(this.DataMember);
}
}
}
public override System.ComponentModel.ISite Site {
get { return base.Site; }
set {
//runs at design time to initiate ContainerControl
base.Site = value;
if (value == null)
return;
// Requests an IDesignerHost service using Component.Site.GetService()
IDesignerHost service = (IDesignerHost)value.GetService(typeof(IDesignerHost));
if (service == null)
return;
if ((service.RootComponent as Form != null)) {
_form = (Form)service.RootComponent;
} else if ((service.RootComponent as UserControl != null)) {
_usercontrol = (UserControl)service.RootComponent;
}
}
}
public System.Windows.Forms.Form GetFormInstance()
{
if (_form == null & this.CurrencyManager.Bindings.Count > 0) {
_form = this.CurrencyManager.Bindings[0].Control.FindForm();
}
return _form;
}
/// <summary>
/// Returns the First Instance of the specified User Control
/// </summary>
/// <returns>System.Windows.Forms.Control</returns>
public System.Windows.Forms.Control GetUserControlInstance()
{
if (_usercontrol == null & this.CurrencyManager.Bindings.Count > 0) {
System.Windows.Forms.Control[] _uControls = null;
_uControls = this.CurrencyManager.Bindings[0].Control.FindForm().Controls.Find(this.Site.Name.ToString(), true);
_usercontrol = _uControls[0];
}
return _usercontrol;
}
public BindingSourceExIsDirty()
{
DataMemberChanged += _DataMemberChanged;
DataSourceChanged += _DataSourceChanged;
BindingComplete += _BindingComplete;
}
// PositionChanged
private override void _PositionChanged(object sender, EventArgs e)
{
if (IsCurrentDirty) {
// IsAutoSavingEvent
if (AutoSave | MessageBox.Show(_msg, "Confirm Save", MessageBoxButtons.YesNo) == DialogResult.Yes) {
try {
//cast table as ITableUpdate to get the Update method
// CType(_dataTable, ITableUpdate).Update()
} catch (Exception ex) {
MessageBox.Show(ex, "Position Changed Error");
// - needs to raise an event
}
} else {
this.CancelEdit();
_dataTable.RejectChanges();
}
IsCurrentDirty = false;
}
base(e);
}
#endregion
}
【讨论】：
从我更新的问题中，我发现我必须使用 Memberwise.Clone 在 BeginEdit 中存储对象的当前版本，然后在 CancelEdit 中将其恢复为当前版本。
【讨论】：
BindingSource 没有任何 BeginEdit 和 EndEdit 事件，是吗？我也在尝试在正确的时间获取我的对象的副本，但我很挣扎。 :(
我总是做的是捕捉控件的各个“更改”事件。在下面的示例中，我在此示例中使用了选项卡控件。 Try/Catch 是一个肮脏的解决方案，不必处理各种异常；-)
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'
' some code
'
BindingNavigatorSaveItem.Enabled = False
For Each tabctl As Control In Me.TabControl1.Controls
For Each ctl As Control In tabctl.Controls
Try
If ctl.GetType Is GetType(TextBox) Then
AddHandler DirectCast(ctl, TextBox).TextChanged, AddressOf GenDataChanged
ElseIf ctl.GetType Is GetType(NumericUpDown) Then
AddHandler DirectCast(ctl, NumericUpDown).ValueChanged, AddressOf GenDataChanged
ElseIf ctl.GetType Is GetType(ComboBox) Then
AddHandler DirectCast(ctl, ComboBox).SelectedValueChanged, AddressOf GenDataChanged
ElseIf ctl.GetType Is GetType(CheckBox) Then
AddHandler DirectCast(ctl, CheckBox).CheckStateChanged, AddressOf GenDataChanged
End If
Catch ex As Exception
End Try
Next
Next
End Sub
Private Sub GenDataChanged(sender As System.Object, e As System.EventArgs)
BindingNavigatorSaveItem.Enabled = True
End Sub
【讨论】：
我不确定在提问时它是否可用，但我使用的是 grid_CurrentCellDirtyStateChanged;事件
【讨论】：
首先确定你设置了 DataSourceUpdateMode.OnPropertyChanged
txrFirstName.DataBindings.Add("Text", bindingSource1, "FirstName", false,DataSourceUpdateMode.OnPropertyChanged);
然后将此代码添加到您的 movenext 点击事件中
if (((DataRowView)bindingSource1.Current).IsNew)
{
MessageBox.Show("Current Row IsNew");
}
if (((DataRowView)bindingSource1.CurrencyManager.Current).Row.HasVersion(DataRowVersion.Proposed))
{
MessageBox.Show("Current Row Modified");
DialogResult dialogResult = MessageBox.Show("Current Row Modified", "Some Title", MessageBoxButtons.YesNo);
if (dialogResult == DialogResult.Yes)
{
//do something
((DataRowView)bindingSource1.CurrencyManager.Current).Row.AcceptChanges();
}
else if (dialogResult == DialogResult.No)
{
//do something else
((DataRowView)bindingSource1.CurrencyManager.Current).Row.RejectChanges();
}
}
else {
bindingSource1.MoveNext();
}
【讨论】：