Dynamic DataGridViewComboBox Column - custom-controls

Question

I am trying to make a DataGridViewComboBox Column that will accept new data and add it to it's list items.
I am building this for a quoting system I sort of did this another way but I just couldn't get it to function reliably.
I keep getting a System.NullReferenceException on the OnSelectedIndexChanged.
I want to be able to type a value into the the ComboBox cell have it added to the list items in order.
Can someone help me out on this?
#region DataGridViewVariableComboBoxColumn
public class DataGridViewVariableComboBoxColumn : DataGridViewComboBoxColumn
{
[Browsable(true)]
[Category("Behavior")]
[DefaultValue(false)]
public bool AddNewItems { get; set; }
private System.Windows.Forms.AutoCompleteMode comboxAutoCompleteMode;
[Browsable(true)]
[Category("Behavior")]
[DefaultValue(false)]
public System.Windows.Forms.AutoCompleteMode ComboBoxAutoCompleteMode
{
get { return comboxAutoCompleteMode; }
set
{
comboxAutoCompleteMode = value;
}
}
public DataGridViewVariableComboBoxColumn()
{
this.CellTemplate = new DataGridViewVariableComboBoxCell();
}
public override DataGridViewCell CellTemplate
{
get
{
return base.CellTemplate;
}
set
{
if (value != null &&
!value.GetType().IsAssignableFrom(typeof(DataGridViewVariableComboBoxCell)))
{
throw new InvalidCastException("Must be a DataGridViewVariableComboBoxCell");
}
base.CellTemplate = value;
}
}
public override object Clone()
{
var c = (DataGridViewVariableComboBoxColumn)base.Clone();
if (c != null)
{
c.AddNewItems = this.AddNewItems;
c.ComboBoxAutoCompleteMode = this.ComboBoxAutoCompleteMode;
c.DisplayStyle = this.DisplayStyle;
c.FlatStyle = this.FlatStyle;
}
return c;
}
}
public class DataGridViewVariableComboBoxCell : DataGridViewComboBoxCell
{
public DataGridViewVariableComboBoxCell() : base()
{
}
public override object Clone()
{
DataGridViewVariableComboBoxCell cell = base.Clone() as DataGridViewVariableComboBoxCell;
return cell;
}
public override void InitializeEditingControl(int rowIndex, object initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
{
try
{
base.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle);
DataGridViewVariableComboBoxEditingControl TheControl = (DataGridViewVariableComboBoxEditingControl)DataGridView.EditingControl;
var c = (DataGridViewVariableComboBoxColumn)this.OwningColumn;
TheControl.OwningColumn = this.OwningColumn;
TheControl.AddNewItems = c.AddNewItems;
TheControl.EditingComboBoxAutoCompleteMode = c.ComboBoxAutoCompleteMode;
TheControl.EditingAutoCompleteSource = AutoCompleteSource.ListItems;
TheControl.EditingComboBoxStyle = ComboBoxStyle.DropDown;
if (TheControl != null)
{
TheControl.SelectedIndex = 0;
}
}
catch { }
}
public override Type EditType
{
get
{
return typeof(DataGridViewVariableComboBoxEditingControl);
}
}
public override Type ValueType
{
get
{
// Return the type of the value that DataGridViewVariableComboBoxCell contains.
return typeof(string);
}
}
}
internal class DataGridViewVariableComboBoxEditingControl : DataGridViewComboBoxEditingControl, IDataGridViewEditingControl
{
private DataGridView dataGridViewControl;
private int rowIndex;
private bool valueChanged = false;
public System.Windows.Forms.AutoCompleteMode EditingComboBoxAutoCompleteMode
{
get
{return this.AutoCompleteMode; }
set
{
this.AutoCompleteMode = value;
}
}
public ComboBoxStyle EditingComboBoxStyle
{
get
{ return this.DropDownStyle; }
set
{
this.DropDownStyle = value;
}
}
public AutoCompleteSource EditingAutoCompleteSource
{
get
{ return this.AutoCompleteSource; }
set
{
this.AutoCompleteSource = value;
}
}
public DataGridViewVariableComboBoxEditingControl() : base()
{
}
public bool AddNewItems { get; set; }
public DataGridViewColumn OwningColumn { get; set; }
private string editingControlFormattedValue;
public string EditingControlFormattedValue
{
get
{
return editingControlFormattedValue;
}
set
{
editingControlFormattedValue = value;
}
}
public object GetEditingControlFormattedValue(DataGridViewDataErrorContexts context)
{
editingControlFormattedValue = this.Text;
if (this.SelectedIndex == -1 && this.AddNewItems && editingControlFormattedValue != "")
{
List<string> list = new List<string>();
if (this.Items.Count > 0)
{
list = this.Items.Cast<string>()
.Select(x => x)
.ToList();
}
else
{
list = new List<string>();
}
if (!list.Contains(editingControlFormattedValue) && editingControlFormattedValue != "")
{
list.Add(editingControlFormattedValue);
list = list.Distinct().OrderBy(o => o).ToList();
}
((DataGridViewVariableComboBoxColumn)OwningColumn).Items.Clear();
((DataGridViewVariableComboBoxColumn)OwningColumn).Items.AddRange(list.ToArray());
this.Items.Clear();
this.Items.AddRange(list.ToArray());
int index = ((DataGridViewVariableComboBoxColumn)OwningColumn).Items.IndexOf(editingControlFormattedValue);
EditingControlValueChanged = true;
//base.SelectedIndex = index;
//this.Text = text;
// EditingControlDataGridView.NotifyCurrentCellDirty(true);
}
return editingControlFormattedValue;
}
public DataGridView EditingControlDataGridView
{
get
{
return dataGridViewControl;
}
set
{
dataGridViewControl = value;
}
}
public int EditingControlRowIndex
{
get
{
return rowIndex;
}
set
{
rowIndex = value;
}
}
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 false;
}
}
// 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
// .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 OnSelectedIndexChanged(EventArgs e)
{
if (valueChanged)
{
base.OnSelectedIndexChanged(e);
}
}
protected override void OnSelectedValueChanged(EventArgs e)
{
if (valueChanged)
{
base.OnSelectedValueChanged(e);
}
}
protected override void OnSelectedItemChanged(EventArgs e)
{
if (valueChanged)
{
base.OnSelectedItemChanged(e);
}
}
}
#endregion