format datetimepicker in datagridview column

Question

I am trying to use the DateTime picker custom gridview column type from this MSDN example on How to host controls in DataGridViewCells. I want to display hour and minute in 24 hour format, without seconds or AM PM indicators.

I have set EditingControlFormattedValue to "HH:mm", and when not actually editing the value is displayed correctly.

When editing, if in the constructor of the CalendarEditingControl I set the editing control to CustomFormat = "HH:mm", the control displays the day of week and month. (!?)

When I instead use Format = DateTimePickerFormat.Time, the control shows AM or PM when editing.

How can I persuade this control to display only the parts of the DateTime value that I care about? (C#, VS 2008)

Answer 1

There are a few tweaks you need to to do the linked code to make it work the way you want:

• Comment out the hard-coded line in CalendarCell() constructor (this.Style.Format = "d";)

• Tell the CalendarEditingControl to use your custom-specified format:

• In the designer, set the format you want (EditColumns->DefaultCellStyle->Format)

  public void ApplyCellStyleToEditingControl(DataGridViewCellStyle dataGridViewCellStyle)
  {
      this.Format = DateTimePickerFormat.Custom;
      this.CustomFormat = dataGridViewCellStyle.Format;
      // ... other stuff
  }
  

Answer 2

I found I needed to make the following changes:

In the constructor of the CalendarCell change the format to 24 hour.

public CalendarCell()
    : base()
{
    // Use the 24hr format.
     //this.Style.Format = "d";
     this.Style.Format = "HH:mm";
}

In the constructor for the editing control specify to use a custom format. I've also taken the liberty of setting ShowUpDown true so you don't show the calendar icon when editing the cell:

public CalendarEditingControl()
{
    //this.Format = DateTimePickerFormat.Short;
    this.Format = DateTimePickerFormat.Custom;
    this.CustomFormat = "HH:mm";
    this.ShowUpDown = true;
}

Change EditingControlFormattedValue. This doesn't appear to actually be necessary but feels icky to leave as is.

// Implements the IDataGridViewEditingControl.EditingControlFormattedValue 
// property.
public object EditingControlFormattedValue
{
    get
    {
        //return this.Value.ToShortDateString();
        return this.Value.ToString("HH:mm");
    }
    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.Value = DateTime.Parse((String)value);
            }
            catch
            {
                // In the case of an exception, just use the 
                // default value so we're not left with a null
                // value.
                this.Value = DateTime.Now;
            }
        }
    }
}