I am trying to create an autocomplete column using DataGridView in WinForms using C#. I have managed to get it working using EditingControlShowing event of DataGridView and is working fine.
However, as per normal AutoComplete textbox, the filtered list shows only data filtering based on "Starting With". To resolve this, I have used an AutoComplete TextBox from here that allows substring search using a custom Listbox.
Taking this custom control as base, I created a custom control inheriting DataGridViewColumn. The problem is the ListBox control doesn't show inline with the gridview cell. Here's the code -
public class DataGridViewAutoCompleteColumn : DataGridViewColumn
{
public DataGridViewAutoCompleteColumn()
: base(new DataGridViewAutoCompleteCell())
{
}
public override DataGridViewCell CellTemplate
{
get
{
return base.CellTemplate;
}
set
{
// Ensure that the cell used for the template is a DataGridViewAutoCompleteCell.
if (value != null &&
!value.GetType().IsAssignableFrom(typeof(DataGridViewAutoCompleteCell)))
{
throw new InvalidCastException("Must be a DataGridViewAutoCompleteCell");
}
base.CellTemplate = value;
}
}
}
public class DataGridViewAutoCompleteCell : DataGridViewTextBoxCell
{
public DataGridViewAutoCompleteCell()
: base()
{
// Use the short date format.
this.Style.Format = "d";
}
public override void InitializeEditingControl(int rowIndex, object
initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
{
// Set the value of the editing control to the current cell value.
base.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle);
AutoCompleteEditingControl ctl = DataGridView.EditingControl as AutoCompleteEditingControl;
ctl.AutoCompleteList = this.AutoCompleteList;
// Use the default row value when Value property is null.
if (this.Value == null)
{
ctl.Text = (string)this.DefaultNewRowValue;
}
else
{
ctl.Text = (string)this.Value;
}
}
public override Type EditType
{
get
{
// Return the type of the editing control that DataGridViewAutoCompleteCell uses.
return typeof(AutoCompleteEditingControl);
}
}
public override Type ValueType
{
get
{
// Return the type of the value that DataGridViewAutoCompleteCell contains.
return typeof(String);
}
}
public override object DefaultNewRowValue
{
get
{
// Use the current date and time as the default value.
return string.Empty;
// return DateTime.Now;
}
}
public List<String> AutoCompleteList { get; set; }
}
class AutoCompleteEditingControl : AutoCompleteTextbox, IDataGridViewEditingControl
{
DataGridView dataGridView;
private bool valueChanged = false;
int rowIndex;
public AutoCompleteEditingControl()
{
}
// Implements the IDataGridViewEditingControl.EditingControlFormattedValue
// property.
public object EditingControlFormattedValue
{
get
{
return this.Text;
}
set
{
if (value is String)
{
try
{
// This will throw an exception of the string is
// null, empty, or not in the format of a date.
this.Text = (String)value;
}
catch
{
// In the case of an exception, just use the
// default value so we're not left with a null
// value.
this.Text = String.Empty;
}
}
}
}
// Implements the
// IDataGridViewEditingControl.GetEditingControlFormattedValue method.
public object GetEditingControlFormattedValue(
DataGridViewDataErrorContexts context)
{
return EditingControlFormattedValue;
}
// Implements the
// IDataGridViewEditingControl.ApplyCellStyleToEditingControl method.
public void ApplyCellStyleToEditingControl(
DataGridViewCellStyle dataGridViewCellStyle)
{
this.Font = dataGridViewCellStyle.Font;
this.ForeColor = dataGridViewCellStyle.ForeColor;
this.BackColor = dataGridViewCellStyle.BackColor;
}
// Implements the IDataGridViewEditingControl.EditingControlRowIndex
// property.
public int EditingControlRowIndex
{
get
{
return rowIndex;
}
set
{
rowIndex = value;
}
}
// Implements the IDataGridViewEditingControl.EditingControlWantsInputKey
// method.
public bool EditingControlWantsInputKey(
Keys key, bool dataGridViewWantsInputKey)
{
// Let the DateTimePicker handle the keys listed.
switch (key & Keys.KeyCode)
{
case Keys.Left:
case Keys.Up:
case Keys.Down:
case Keys.Right:
case Keys.Home:
case Keys.End:
case Keys.PageDown:
case Keys.PageUp:
return true;
default:
return !dataGridViewWantsInputKey;
}
}
// Implements the IDataGridViewEditingControl.PrepareEditingControlForEdit
// method.
public void PrepareEditingControlForEdit(bool selectAll)
{
// No preparation needs to be done.
}
// Implements the IDataGridViewEditingControl
// .RepositionEditingControlOnValueChange property.
public bool RepositionEditingControlOnValueChange
{
get
{
return false;
}
}
// Implements the IDataGridViewEditingControl
// .EditingControlDataGridView property.
public DataGridView EditingControlDataGridView
{
get
{
return dataGridView;
}
set
{
dataGridView = value;
}
}
// Implements the IDataGridViewEditingControl
// .EditingControlValueChanged property.
public bool EditingControlValueChanged
{
get
{
return valueChanged;
}
set
{
valueChanged = value;
}
}
// Implements the IDataGridViewEditingControl
// .EditingPanelCursor property.
public Cursor EditingPanelCursor
{
get
{
return base.Cursor;
}
}
protected override void OnTextChanged(EventArgs eventargs)
{
// Notify the DataGridView that the contents of the cell
// have changed.
valueChanged = true;
this.EditingControlDataGridView.NotifyCurrentCellDirty(true);
base.OnTextChanged(eventargs);
}
}
Please advise on what wrong am I doing here.
