Knowledge Base Nr: 00282 compare.cs - http://www.swe-kaiser.de

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c#: eigene controls durch kombination mehrerer standardcontrols und überladen von OnPaint()

  
//das control vergleich zwei arrays (z.b. textfiles) und stellt die unterschiede farblich dar
//stichwort: windiff für arme.
//die zwei ownerdraw listboxen werden synchronisiert und die ausgewählte zeile
//am unteren rand des controls nochmal untereinander angezeigt. für die 2 listboxen können titel
//vergeben werden. das control passt sich bei größenanderungen automaisch an.

//um ein zusätzliches binary (dll für control) zu vermeiden (nachteil keine unterstützung des
//controls im design-mode von visual studio) und trotzdem einen gewissen komfort beim entwurf zu
//bieten habe ich mich entschieden das control automatisch auf die größe seines Parent auszurichten.
//d.h. im designer kann z.b. ein panel als platzhalter für das neue control verwendet werden.

//usage:
  //create control
    KCompare compareLB = new KCompare();
  //customize colors
    compareLB.colTitle = Color.Green;
    compareLB.colBGTitle = Color.Red;
    ...

  //create a panel within design-mode with the prefered size or dock-style
    panel1.Controls.Add(compareLB);
    this.ResumeLayout();

  //create data to display and fill control
    object[] leftContent = new object[] {
                      "012lulli78ABCDEFGHIJKLMNOPIJKLMNOPQRSTUVWXYZ01QRYZ01234567890",
                      "012345678AIJKLMNOPQVWXYZ01BCDEFGHIJKLMNOPQRSTUVW34567890",
                      "012IJKLMNOPQRSTUVWXYZ01345678ABCDEFGHIJKLMNOPQRSZ01234567890"
                                        };
    object[] rightContent = new object[] {
                      "012345678ABCDEFGHIJKLMNOPIJKLMNOPQRSTUVWXYZ01QRSZ01234567890",
                      "012IJKLMNOPQRSTUVWXYZ01345678ABCDEFGHIJKLMNOPQRSZ01234567890",
                                         };
    bool isEqual = compareLB.Fill("linkes array", leftContent, "rechtes array", rightContent);

//control:
  public class CompareControl : Panel
  {
    private Label lblLeft;
    private Label lblRight;
    private KCompareTextBox tbxLeft;
    private KCompareTextBox tbxRight;
    private ListBox lbxLeft;
    private ListBox lbxRight;
    private HScrollBar hScrollBar;
    private Timer tmrSynchronizeListBoxes;
    private System.ComponentModel.IContainer components;

    //the colors are public so they can be set from outside!
    public Brush brBackground = Brushes.White;

    public Color colTitle = Color.Black;
    public Color colBGTitle = Color.LightGray;

    public Brush brMissing = Brushes.Red;
    public Brush brBGMissing = Brushes.Yellow;

    public Brush brDifferent = Brushes.Green;
    public Brush brBGDifferent = Brushes.Yellow;

    public Brush brEqual = Brushes.Black;
    public Brush brBGEqual = Brushes.White;

    private int scrollHPos = 0;
    private int scrollVPosLB1 = 0;
    private int scrollVPosLB2 = 0;
    private bool bTimerLocked = false;
    private int gnHeightTB = -1;

    public CompareControl()
    {
      InitializeComponent();
    }

    protected override void Dispose( bool disposing )
    {
...
    }

    private void InitializeComponent()
    {
...
    }

    public bool Fill(string leftTitle, object[] leftContent, string rightTitle, object[] rightContent)
    {
      SuspendLayout();

      int max = 0;

      lblLeft.Text = leftTitle;
      lblRight.Text = rightTitle;

      lbxLeft.Items.AddRange(leftContent);
      lbxRight.Items.AddRange(rightContent);

      for (int i=0; i<lbxLeft.Items.Count; i++)
      {
        if (max < lbxLeft.Items[i].ToString().Length)
          max = lbxLeft.Items[i].ToString().Length;
      }
      for (int i=0; i<lbxRight.Items.Count; i++)
      {
        if (max < lbxRight.Items[i].ToString().Length)
          max = lbxRight.Items[i].ToString().Length;
      }

      hScrollBar.Maximum = max;

      //quick check for differences
      bool isEqual = true;

      if (leftContent.Length != rightContent.Length)
      {
        isEqual = false;
      }
      else
      {
        for (int i=0; i<leftContent.Length; i++)
        {
          if (leftContent[i].ToString() != rightContent[i].ToString())
          {
            isEqual = false;
            break;
          }
        }
      }

      ResumeLayout(false);
      return isEqual;
    }

    //can be overwritten and customized (compares two characters -
    //returns 0 if equal and -1(Missing) or 1(Different) otherwise)
    public int CompareTextBoxLines(int nColNo)
    {
        if ((nColNo >= tbxLeft.Text.Length)
            || (nColNo >= tbxRight.Text.Length))
            return -1;

        int diff = Compare(tbxLeft.Text[nColNo], tbxRight.Text[nColNo]);

        return diff;
    }

    //can be overwritten and customized (compares two characters -
    //returns 0 if equal or 1 if different)
    protected int Compare(char leftChar, char rightChar)
    {
      if (leftChar != rightChar)
        return 1;

      return 0;
    }

    //can be overwritten and customized (compares two characters -
    //returns 0 if equal and -1(Missing) or 1(Different) otherwise)
    protected int CompareListBoxLines(int nLineNo, int nColNo)
    {
      if ((nLineNo >= lbxLeft.Items.Count)
      || (nLineNo >= lbxRight.Items.Count))
      return -1;

      if ((nColNo >= lbxLeft.Items[nLineNo].ToString().Length)
        || (nColNo >= lbxRight.Items[nLineNo].ToString().Length))
        return -1;

      int diff = Compare(lbxLeft.Items[nLineNo].ToString()[nColNo]
        , lbxRight.Items[nLineNo].ToString()[nColNo]);

      return diff;
    }

    private void panel_Resize(object sender, EventArgs e)
    {
      Size size = Size;

      int nHeightL = lblLeft.Size.Height;
      int nHeightTB = tbxLeft.Size.Height;
      int nHeightSB = hScrollBar.Size.Height;
      int nWidthLB = size.Width / 2;
      int nHeightLB = size.Height - nHeightSB - nHeightL - 2*nHeightTB;

      if (gnHeightTB < 0)
        gnHeightTB = nHeightTB;
      else
        nHeightTB = gnHeightTB;

      lblLeft.Location = new Point(0, 0);
      lblLeft.Size = new Size(nWidthLB, nHeightL);

      lblRight.Location = new Point(nWidthLB, 0);
      lblRight.Size = new Size(nWidthLB, nHeightL);

      lbxLeft.Location = new Point(0, nHeightL);
      lbxLeft.Size = new Size(nWidthLB, nHeightLB);

      lbxRight.Location = new Point(nWidthLB, nHeightL);
      lbxRight.Size = new Size(nWidthLB, nHeightLB);

      hScrollBar.Location = new Point(0, nHeightLB + nHeightL);
      hScrollBar.Size = new Size(size.Width, nHeightSB);

      tbxLeft.Location = new Point(0, nHeightL + nHeightLB + nHeightSB);
      tbxLeft.Size = new Size(size.Width, gnHeightTB-1);

      tbxRight.Location = new Point(0, nHeightL + nHeightLB + nHeightSB + nHeightTB);
      tbxRight.Size = new Size(size.Width, gnHeightTB-1);
    }

    private void DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
    {
      ListBox listbox = (ListBox)sender;
      Font font = listbox.Font;

      SuspendLayout();

      e.DrawBackground();

      e.Graphics.FillRectangle(brBackground, e.Bounds);

      bool selected = ((e.State & DrawItemState.Selected) == DrawItemState.Selected) ? true : false;

      string displayText = listbox.Items[e.Index].ToString();

      Size cs = TextRenderer.MeasureText("Q", Font);
      int fontWidth = cs.Width;
      int fontHeight = cs.Height;

      Point pos = new Point(e.Bounds.X, e.Bounds.Y);

      //e.Graphics.DrawString(displayText, font, Brushes.Black, pos); //e.Bounds);
      for (int i=0; i<displayText.Length; i++)
      {
        int startPos = i - scrollHPos;
        if (startPos >= 0)
        {

          pos.X = startPos * fontWidth;

          int nDiff = CompareListBoxLines(e.Index, i);

          Brush textBrush;
          Brush textBGBrush;

          if (nDiff < 0)
          {
            textBrush = brMissing;
            textBGBrush = brBGMissing;
          }
          else if (nDiff > 0)
          {
            textBrush = brDifferent;
            textBGBrush = brBGDifferent;
          }
          else
          {
            textBrush = brEqual;
            textBGBrush = brBGEqual;
          }

          Rectangle rect = new Rectangle(pos, new Size(fontWidth, fontHeight));
          e.Graphics.FillRectangle(textBGBrush, rect);

          e.Graphics.DrawString(displayText.Substring(i, 1), font, textBrush, pos);
        }
      }

      if (selected) //draw focus rectangle
      {
          //todo: why do e.DrawFocusRectangle() NOT work???
          Rectangle rectSelected = e.Bounds;

          rectSelected.X = rectSelected.X + 1;
          rectSelected.Y = rectSelected.Y + 1;
          rectSelected.Width = rectSelected.Width - 2;
          rectSelected.Height = rectSelected.Height - 2;
          e.Graphics.DrawRectangle(SystemPens.WindowText, rectSelected);
      }

      ResumeLayout();
    }

    private void listBox1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
    {
      DrawItem(sender, e);
    }

    private void listBox2_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
    {
      DrawItem(sender, e);
    }

    private void SyncListBox2(int index)
    {
      if (index < 0)
          return;

      scrollVPosLB1 = lbxLeft.TopIndex;
      if (scrollVPosLB1 < lbxRight.Items.Count)
      {
        lbxRight.TopIndex = scrollVPosLB1;
        if (index < lbxRight.Items.Count)
            lbxRight.SelectedIndex = index;
        else
            lbxRight.SelectedIndex = -1;
      }
      else
      {
        lbxRight.TopIndex = 0;
        lbxRight.SelectedIndex = -1;
      }
    }

    private void SyncListBox1(int index)
    {
      if (index < 0)
          return;

      scrollVPosLB2 = lbxRight.TopIndex;
      if (scrollVPosLB2 < lbxLeft.Items.Count)
      {
        lbxLeft.TopIndex = scrollVPosLB2;
        if (index < lbxLeft.Items.Count)
            lbxLeft.SelectedIndex = index;
        else
            lbxLeft.SelectedIndex = -1;
      }
      else
      {
        lbxLeft.TopIndex = 0;
        lbxLeft.SelectedIndex = -1;
      }
    }

    private void ShowDifferencesWithinTextboxes(int index)
    {
      if ((index >= 0) && (index < lbxLeft.Items.Count))
          tbxLeft.Text = lbxLeft.Items[index].ToString();
      else
          tbxLeft.Text = "";

      if ((index >= 0) && (index < lbxRight.Items.Count))
          tbxRight.Text = lbxRight.Items[index].ToString();
      else
          tbxRight.Text = "";
    }

    private void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
    {
      bTimerLocked = true;
      SyncListBox2(((ListBox)sender).SelectedIndex);

      ShowDifferencesWithinTextboxes(((ListBox)sender).SelectedIndex);
      bTimerLocked = false;
    }

    private void listBox1_MouseDown(object sender, MouseEventArgs e)
    {
      bTimerLocked = true;

      //((ListBox)sender).SelectedItem differs between VS2003 and VS2005 !!!
      //calculate the clicked item from mouseevent and height of an entry
      int index = e.Y / ((ListBox)sender).ItemHeight;
      SyncListBox2(index);

      ShowDifferencesWithinTextboxes(index);
      bTimerLocked = false;
    }

    private void listBox2_SelectedIndexChanged(object sender, System.EventArgs e)
    {
      bTimerLocked = true;
      SyncListBox1(lbxRight.SelectedIndex);

      ShowDifferencesWithinTextboxes(lbxRight.SelectedIndex);
      bTimerLocked = false;
    }

    private void listBox2_MouseDown(object sender, MouseEventArgs e)
    {
      bTimerLocked = true;

      //((ListBox)sender).SelectedItem differs between VS2003 and VS2005 !!!
      //calculate the clicked item from mouseevent and height of an entry
      int index = e.Y / ((ListBox)sender).ItemHeight;
      SyncListBox1(index);

      ShowDifferencesWithinTextboxes(index);
      bTimerLocked = false;
    }

    private void hScrollBar1_ValueChanged(object sender, System.EventArgs e)
    {
      scrollHPos = ((HScrollBar)sender).Value;
      lbxLeft.Invalidate();
      lbxLeft.Update();
      lbxRight.Invalidate();
      lbxRight.Update();
    }

    private void timer1_Tick(object sender, System.EventArgs e)
    {
      if (bTimerLocked)
          return;

      bTimerLocked = true;
      if (scrollVPosLB1 != lbxLeft.TopIndex)
      {
          SyncListBox2(lbxLeft.SelectedIndex);
          ShowDifferencesWithinTextboxes(lbxLeft.SelectedIndex);
      }

      if (scrollVPosLB2 != lbxRight.TopIndex)
      {
          SyncListBox1(lbxRight.SelectedIndex);
          ShowDifferencesWithinTextboxes(lbxRight.SelectedIndex);
      }
      bTimerLocked = false;
    }
  }

  public class KCompareTextBox : Label    //TextBox: causes problems if clicked (font...)
  {
    public KCompareTextBox()
    {
        //absolutely necessary to make OnPaint() work
        SetStyle(ControlStyles.UserPaint, true);
        SetStyle(ControlStyles.AllPaintingInWmPaint, true);
    }

    protected override void OnPaint(PaintEventArgs e)
    {
      base.OnPaint(e);

      e.Graphics.FillRectangle(((CompareControl)Parent).brBackground, e.ClipRectangle);

      string displayText = Text;

      Size cs = TextRenderer.MeasureText("Q", Font);
      int fontWidth = cs.Width;
      int fontHeight = cs.Height;

      Point pos = new Point(e.ClipRectangle.X, e.ClipRectangle.Y);

      //e.Graphics.DrawString(displayText, font, Brushes.Black, pos); //e.Bounds);
      for (int i=0; i<displayText.Length; i++)
      {
        pos.X = i * fontWidth;

        int nDiff = ((CompareControl)Parent).CompareTextBoxLines(i);

        Brush textBrush;
        Brush textBGBrush;

        if (nDiff < 0)
        {
          textBrush = ((CompareControl)Parent).brMissing;
          textBGBrush = ((CompareControl)Parent).brBGMissing;
        }
        else if (nDiff > 0)
        {
          textBrush = ((CompareControl)Parent).brDifferent;
          textBGBrush = ((CompareControl)Parent).brBGDifferent;
        }
        else
        {
          textBrush = ((CompareControl)Parent).brEqual;
          textBGBrush = ((CompareControl)Parent).brBGEqual;
        }

        Rectangle rect = new Rectangle(pos, new Size(fontWidth, fontHeight));
        e.Graphics.FillRectangle(textBGBrush, rect);

        e.Graphics.DrawString(displayText.Substring(i, 1), Font, textBrush, pos);
      }
    }
  }