Build Your Own DataGrid for Silverlight: Step 3


// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System;

namespace Open.Windows.Controls
{
    public class TextCell : Cell
    {
        public static readonly DependencyProperty TextProperty;

        static TextCell()
        {
            TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(TextCell), null);
        }

        public TextCell()
        {
            DefaultStyleKey = typeof(TextCell);
        }

        public string Text
        {
            get { return (string)GetValue(TextProperty); }
            set { SetValue(TextProperty, value); }
        }

        private Panel textContainerElement;
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            textContainerElement = GetTemplateChild("TextContainerElement") as Panel;
        }

        private void textBoxElement_TextChanged(object sender, TextChangedEventArgs e)
        {
            if (this.CellState == CellState.Edited)
                this.IsDirty = true;
        }

        private CellTextBox textBoxElement;
        protected override bool OnBeginEdit()
        {
            if (textContainerElement != null)
            {
                if (textBoxElement == null)
                {
                    textBoxElement = new CellTextBox();
                    textBoxElement.Style = ResourceHelper.FindResource("CellTextBoxStyle") as Style;
                    textBoxElement.Text = this.Text;
                    textBoxElement.Margin = this.Padding;
                    textBoxElement.HorizontalAlignment = this.HorizontalContentAlignment;
                    textBoxElement.VerticalAlignment = this.VerticalContentAlignment;
                    textBoxElement.Foreground = this.Foreground;
                    textBoxElement.TextChanged += new TextChangedEventHandler(textBoxElement_TextChanged);

                    textContainerElement.Children.Add(textBoxElement);
                }

                if (textBoxElement.Focus())
                {
                    textBoxElement.SelectionStart = textBoxElement.Text.Length;
                    return true;
                }
            }

            return false;
        }

        private long lastTick;
        protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
        {
            base.OnMouseLeftButtonDown(e);

            if (this.CellState == CellState.Focused)
                BeginEdit();

            if (this.CellState == CellState.Edited)
            {
                e.Handled = true; //we do not want that the ContainerItem OnMouseLeftButtonDown is called

                if (DateTime.Now.Ticks - lastTick < 2000000) //It is a double click
                    DoubleClick();
            }

            lastTick = DateTime.Now.Ticks;
            if (textBoxElement != null)
                textBoxElement.LastTick = lastTick;

        }

        private void DoubleClick()
        {
            if (textBoxElement != null)
                textBoxElement.SelectAll();
        }

        protected override void OnCommitEdit()
        {
            if (textBoxElement != null)
                this.Text = textBoxElement.Text;
        }

        protected override void OnCancelEdit()
        {
            if (textBoxElement != null)
                textBoxElement.Text = this.Text;
        }

        protected override void OnKeyDown(KeyEventArgs e)
        {
            if (CellState != CellState.Edited)
            {
                switch (e.Key)
                {
                    case Key.Left:
                    case Key.Up:
                    case Key.Down:
                    case Key.Right:
                    case Key.PageDown:
                    case Key.PageUp:
                    case Key.Home:
                    case Key.End:
                    case Key.Enter:
                    case Key.Ctrl:
                    case Key.Shift:
                    case Key.Alt:
                    case Key.Escape:
                    case Key.Tab:
                        break;

                    default:
                        if (BeginEdit() && (textBoxElement != null))
                            textBoxElement.Text = "";
                        break;
                }
            }

            base.OnKeyDown(e);
        }

        protected override object CurrentValue
        {
            get { return this.Text; }
        }

        protected override object DirtyValue
        {
            get
            {
                if (textBoxElement != null)
                    return textBoxElement.Text;

                return this.Text;
            }
        }

        protected override void AfterEdit()
        {
            if ((textBoxElement != null) && (textContainerElement != null)) 
            {
                if (textBoxElement == FocusManager.GetFocusedElement())
                    this.Focus();

                textContainerElement.Children.Remove(textBoxElement);
                textBoxElement.TextChanged -= new TextChangedEventHandler(textBoxElement_TextChanged);

                textBoxElement = null;
            }
        }
    }
}