Soft Build

I had to write an application where I used a DataGridView with various DataTypes columns. For the dateTime column I used a Calendar Column, but for the Int32 columns, I wanted to display a message that would say to the user that they inserted some wrong data. I have found an example on http://www.codeguru.com/forum/showthread.php?t=418306 , but the example is in VB.NET. I wrote something in C#:

private void callOnEdit(object sender, DataGridViewDataErrorEventArgs e){
try
{
switch (e.ColumnIndex) {
case 1: MessageBox.Show(“Message.”);break;
//and so on
}
}
catch
{
MessageBox.Show(“Message!”);
}
}

To use this, you only have to go in the Events panel for the DataGridView and set the DataError event to be handled by this function.

Please note that in VB.NET you can use “Handles”, but in C# you can’t. This is why:

http://www.velocityreviews.com/forums/t367616-using-quothandlesquot-vb-vs-c.html

If you have a DataGridView and want to be fancy and add a calendar column, here is the code (I found it on http://msdn2.microsoft.com/en-us/library/7tas5c80.aspx):

using System;
using System.Windows.Forms;

public class CalendarColumn : DataGridViewColumn
{
public CalendarColumn() : base(new CalendarCell())
{
}

public override DataGridViewCell CellTemplate
{
get
{
return base.CellTemplate;
}
set
{
// Ensure that the cell used for the template is a CalendarCell.
if (value != null &&
!value.GetType().IsAssignableFrom(typeof(CalendarCell)))
{
throw new InvalidCastException(“Must be a CalendarCell”);
}
base.CellTemplate = value;
}
}
}

public class CalendarCell : DataGridViewTextBoxCell
{

public CalendarCell()
: 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);
CalendarEditingControl ctl =
DataGridView.EditingControl as CalendarEditingControl;
ctl.Value = (DateTime)this.Value;
}

public override Type EditType
{
get
{
// Return the type of the editing contol that CalendarCell uses.
return typeof(CalendarEditingControl);
}
}

public override Type ValueType
{
get
{
// Return the type of the value that CalendarCell contains.
return typeof(DateTime);
}
}

public override object DefaultNewRowValue
{
get
{
// Use the current date and time as the default value.
return DateTime.Now;
}
}
}

class CalendarEditingControl : DateTimePicker, IDataGridViewEditingControl
{
DataGridView dataGridView;
private bool valueChanged = false;
int rowIndex;

public CalendarEditingControl()
{
this.Format = DateTimePickerFormat.Short;
}

// Implements the IDataGridViewEditingControl.EditingControlFormattedValue
// property.
public object EditingControlFormattedValue
{
get
{
return this.Value.ToShortDateString();
}
set
{
if (value is String)
{
this.Value = DateTime.Parse((String)value);
}
}
}

// 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.CalendarForeColor = dataGridViewCellStyle.ForeColor;
this.CalendarMonthBackground = 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 OnValueChanged(EventArgs eventargs)
{
// Notify the DataGridView that the contents of the cell
// have changed.
valueChanged = true;
this.EditingControlDataGridView.NotifyCurrentCellDirty(true);
base.OnValueChanged(eventargs);
}
}

Ok, now to add it to your DataGridView, you can do like this:

CalendarColumn col = new CalendarColumn();
col.Name = “data”;
col.ValueType = typeof(System.DateTime);
col.HeaderText= “Date”

yourDataGrid.Columns.Add(col);