How to tell if user has modified data using bindingsource?

Question

I have a DataGridView bound to a bindingsource which is bound to a List. The user clicks a row that goes to a form with textboxes, etc. The textboxes a

Answer 1

I know this is an old post but here is an Extended BindingSource with IsDirtyFlag - you can adapt it how you would like - I pulled this code from another posting somewhere on the net years ago - made some very minor changes I think it was originally in VB - I converted to 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;
    }

    /// 

    /// Returns the First Instance of the specified User Control
    /// 
    /// System.Windows.Forms.Control
    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

}