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[ASP.net教程]分享一个带有合计行功能的DataGridView扩展


因为一个Winform的项目中需要用到带有合计行的表格,并且需要满足以下需求:

  1. 合计行可自动对需要求和的列进行求和计算;
  2. 合计行必须固定(冻结)在表格的最底部,且其位置不受滚动条的滚动而移动;
  3. 可以设置合计行单元格的数据展示格式.

本以为winform程序出来已经这么多年了,这个本也是个比较基础的功能,网上应该有很多现成的例子,便想着直接从网上找个例子用到项目中即可,无奈找了很久也没有见一个合适的实现,迫于无奈,只能动手自己写了一个DataGridView的扩展.并在这里整理出来,以分享给后续有类似需求的朋友参考,助其少走一些弯路.

  1. 在开始之前,先来看一下在项目中展示效果及在程序中调用方式(当然展示的数据是随机生成的临时测试数据),各位看得顺眼再继续往后.
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  2. 实现思路.
             本文中的合计行其实是一个仅有一行数据的DataGridView,即整个控件会包含原数据表格DataGridView及合计行DataGridView组成,一开始本想通过一个UserControl来组织这两个控件,但会遇到DataGridView本身一大堆属性和事件需要在UserControl上重新定义,才能方便的在设计器中直接使用,尝试了几个属性后,发现这个工作量变得非常大,这个模式便被否定了,所以不得不重新寻找一个可行的方案.
            后经转变思维,我们可以直接将控件继承于原生态的DataGridView, 在当前控件展示的的时候,去动态创建一个合计行DataGridView,并将其添加到数据源控件下面即可.几经周折尝试后,发现确实可行,确定这个方向后,我们便一步步来实现这个功能. 完成后总结这个功能点,大致需要处理以下几个问题:
    1)  如何处理DataGridView的滚动条:滚动条需要联动,且滚动条需要位于两个DataGridView的外围;
    2)  如何确定合计行的位置,并将其添加到控件中,使其看起来和原数据表格是一体的;
    3)  当通过属性设置当前控件大小后,如何对应调整合计行的位置及大小;
    4)  拖动列宽后,对应调整合计行的列宽;
    5)  自动合计.
    在接下来的文章中,跟着分解步骤,来一起看看这个的具体实现.
  3. 初始化变量并注册DataGridView相关事件,增加效果处理
    private bool _isShowSumRow = false;       //是否显示合计行private string _sumCellFormat = "N2";      //合计单元格格式化字符串private int _sumRowHeight = 30;         //合计行高private DataGridView _dgvSumRow = null;     //合计行private VScrollBar _vScrollBar = null;     //垂直滚动条private HScrollBar _hScrollBar = null;     //水平滚动条private bool _initSourceGriding = false;    //指示是否正在进行初始gridprivate DockStyle _dock;            //Dockprivate int _dgvSourceMaxHeight = 0;      //dgvSource最大高度private int _dgvSourceMaxWidth = 0;       //dgvSource最大宽度/// <summary>/// 初始化/// </summary>public PDSumDataGridView(){  base.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;  this.ColumnWidthChanged += new DataGridViewColumnEventHandler(this_ColumnWidthChanged);  this.DataSourceChanged += new EventHandler(this_DataSourceChanged);  this.RowHeadersWidthChanged += new EventHandler(this_RowHeadersWidthChanged);  this.MouseWheel += new MouseEventHandler(dgvSource_MouseWheel);}

  4. 禁用DataGridView 默认的滚动条,改为手动添加横向滚动条及纵向滚动条.并将其添加到和DateGridView 相同的父控件上,示例代码如下.
        /// <summary>    /// 初始化合计行    /// </summary>    private void InitSumRowDgv()    {      _dgvSumRow = new DataGridView();      _dgvSumRow.BackgroundColor = this.BackgroundColor;      _dgvSumRow.ColumnHeadersVisible = false;      _dgvSumRow.AllowUserToResizeColumns = false;      _dgvSumRow.AllowUserToResizeRows = false;      _dgvSumRow.ScrollBars = System.Windows.Forms.ScrollBars.None;      _dgvSumRow.Visible = false;      _dgvSumRow.Height = _sumRowHeight;      _dgvSumRow.RowTemplate.Height = _sumRowHeight;      _dgvSumRow.AllowUserToAddRows = false;      _dgvSumRow.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.DisableResizing;      _dgvSumRow.ReadOnly = true;      _dgvSumRow.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;      _dgvSumRow.DefaultCellStyle.SelectionBackColor = _dgvSumRow.DefaultCellStyle.BackColor;      _dgvSumRow.DefaultCellStyle.SelectionForeColor = _dgvSumRow.DefaultCellStyle.ForeColor;      _dgvSumRow.Font = new Font("宋体", 10, FontStyle.Bold);      _dgvSumRow.RowPostPaint += new DataGridViewRowPostPaintEventHandler(dgvSumRow_RowPostPaint);    }    /// <summary>    /// 初始化合计dgv及滚动条    /// </summary>    private void InitSumDgvAndScrolBar()    {      if (this.Parent == null)      {        return;      }      //滚动条      _vScrollBar = new VScrollBar();      _hScrollBar = new HScrollBar();      if (DesignMode)      {        base.ScrollBars = System.Windows.Forms.ScrollBars.Both;      }      else      {        this.ScrollBars = ScrollBars.None;     //禁用dgv默认滚动条       }      this.Parent.Controls.Add(_vScrollBar);      this.Parent.Controls.Add(_hScrollBar);      _vScrollBar.Visible = false;      _hScrollBar.Visible = false;      //注册滚动条事件已代替dgv默认的滚动条      _vScrollBar.Scroll += new ScrollEventHandler(vScrollBar_Scroll);      _hScrollBar.Scroll += new ScrollEventHandler(hScrollBar_Scroll);      InitSumRowDgv();      this.Parent.Controls.Add(_dgvSumRow);      this.SizeChanged += (s, e) =>      {        if (!_initSourceGriding)        {          InitScrollWithSourceGrid();          this.Update();        }      };    }

  5. 根据数据量确定是否需要展示横向及纵向滚动条,同时确定合计行
        /// <summary>    /// 根据源Grid设置是否需展示滚动条    /// </summary>    private void InitScrollWithSourceGrid()    {      if (_initSourceGriding || this.Parent == null)      {        return;      }      //初始化合计行      if (_dgvSumRow == null)      {        InitSumDgvAndScrolBar();      }      _initSourceGriding = true;      if (_dock == DockStyle.Fill)      {        this.Height = Parent.Height;        this.Width = Parent.Width;        this.Location = new Point(0, 0);      }      _dgvSourceMaxHeight = this.Height;      //dgvSource最大高度       _dgvSourceMaxWidth = this.Width;       //dgvSource最大宽度       if (_isShowSumRow)      {        _dgvSourceMaxHeight -= _sumRowHeight;      }      if (_dgvSourceMaxHeight < RowHeight * 2)      {        _initSourceGriding = false;        return;      }      this.Height = _dgvSourceMaxHeight;      var displayDgvSumRowHeight = (_isShowSumRow && !DesignMode) ? _dgvSumRow.Height : 0;      //  this.MouseWheel -= new MouseEventHandler(dgvSource_MouseWheel);      #region 验证是否需要显示水平滚动条      //需要展示水平滚动条      if (this.DisplayedColumnCount(true) < this.Columns.Count)      {        _dgvSourceMaxHeight -= _hScrollBar.Height;        this.Height = _dgvSourceMaxHeight;        _hScrollBar.Location = new Point(this.Location.X, this.Location.Y + this.Height + displayDgvSumRowHeight);        _hScrollBar.Width = _dgvSourceMaxWidth;        _hScrollBar.Visible = true;        _hScrollBar.BringToFront();        _hScrollBar.Minimum = 0;        _hScrollBar.SmallChange = AvgColWidth;        _hScrollBar.LargeChange = AvgColWidth * 2;        _hScrollBar.Maximum = ColsWidth;      }      else      {        _hScrollBar.Visible = false;      }      #endregion      //根据源dgv设置合计行      _dgvSumRow.RowHeadersWidth = this.RowHeadersWidth - 1;      #region 验证是否需要显示纵向滚动条      var dgvSourceDisplayedRowCount = this.DisplayedRowCount(false);   //最多显示行数      //不需要展示垂直滚动条      if (dgvSourceDisplayedRowCount >= this.Rows.Count)      {        _vScrollBar.Visible = false;        this.Width = _dgvSourceMaxWidth;        _dgvSumRow.Width = _dgvSourceMaxWidth;      }      else      {        //需要展示垂直滚动条        _dgvSourceMaxWidth = this.Width - _vScrollBar.Width;       this.Width = _dgvSourceMaxWidth;        _vScrollBar.Height = this.Height + (_isShowSumRow ? _dgvSumRow.Height : 0);        _vScrollBar.Location = new Point(this.Location.X + this.Width, this.Location.Y);        _vScrollBar.Visible = true;        _vScrollBar.Maximum = (this.Rows.Count - dgvSourceDisplayedRowCount + 2) * RowHeight;        _vScrollBar.Minimum = 0;        _vScrollBar.SmallChange = RowHeight;        _vScrollBar.LargeChange = RowHeight * 2;        _vScrollBar.BringToFront();      }      #endregion      if (_isShowSumRow && !DesignMode)      {        _dgvSumRow.Location = new Point(this.Location.X, this.Location.Y + _dgvSourceMaxHeight - 1);        _dgvSumRow.Width = this.Width;        _dgvSumRow.Visible = true;        _dgvSumRow.BringToFront();      }      else      {        _dgvSumRow.Visible = false;      }      _initSourceGriding = false;    }

  6. 处理滚动条事件,同步作用于两个DataGridView
    /// <summary>/// DataGridView 列总宽.用于确定横向滚动条滚动值/// </summary>private int ColsWidth{  get  {    int width = 0;    foreach (DataGridViewColumn col in this.Columns)    {      if (!col.Visible)      {        continue;      }      width += col.Width;    }    return width;  }}/// <summary>/// DataGridView 列平均总宽,用于确定横向滚动条滚动值/// </summary>private int AvgColWidth{  get  {    int width = 80;    width = ColsWidth / this.Columns.Count;    return width;  }}/// <summary>/// 每行高度.用于确定纵向滚动条滚动值/// </summary>private int RowHeight{  get  {    int height = 20;    if (this.Rows.Count > 0)    {      height = (this.Rows[0].Height - 3);    }    return height;  }}/// <summary>/// 处理纵向滚动条事件/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void vScrollBar_Scroll(object sender, ScrollEventArgs e){  this.FirstDisplayedScrollingRowIndex = e.NewValue / RowHeight;}/// <summary>/// 处理横向滚动条事件/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void hScrollBar_Scroll(object sender, ScrollEventArgs e){  int value = e.NewValue;  this.HorizontalScrollingOffset = value;  if (_isShowSumRow && _dgvSumRow != null)  {    _dgvSumRow.HorizontalScrollingOffset = value;  }}/// <summary>/// 处理源dgv鼠标滚轮滚动事件,同步带动横向滚动条及纵向滚动条/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void dgvSource_MouseWheel(object sender, MouseEventArgs e){  if (!_vScrollBar.Visible) return;  if ((_vScrollBar.Value - RowHeight) < 0 && e.Delta > 0)  {    _vScrollBar.Value = _vScrollBar.Minimum;  }  else if ((_vScrollBar.Value + RowHeight * 2) > _vScrollBar.Maximum && e.Delta < 0)  {    _vScrollBar.Value = _vScrollBar.Maximum;  }  else  {    _vScrollBar.Value -= Convert.ToInt32((e.Delta / Math.Abs(e.Delta))) * RowHeight;  }  this.FirstDisplayedScrollingRowIndex = _vScrollBar.Value / RowHeight;}

  7. 拖动列宽改变的时候,同步更新合计行的列宽
    private void this_ColumnWidthChanged(object sender, DataGridViewColumnEventArgs e){  if (_dgvSumRow != null)  {    _dgvSumRow.Columns[e.Column.Index].Width = e.Column.Width;  }}private void this_RowHeadersWidthChanged(object sender, EventArgs e){  if (_dgvSumRow != null)  {    _dgvSumRow.RowHeadersWidth = this.RowHeadersWidth - 1;  }}

  8. 根据设置的需要合计列,自动合计数据
    /// <summary>/// 需要添加合计的datagridviewrow 列名称/// </summary>[Description("获取或设置需要用于求和的列名")]public string[] SumColumns{  get;  set;}/// <summary>/// 合计数据/// </summary>private void SumData(){  if (this.Columns.Count <= 0)  {    return;  }  if (_dgvSumRow.Columns.Count != this.Columns.Count)  {    AddDgvSumRowColumns();  }  if (_dgvSumRow.Rows.Count != 1)  {    _dgvSumRow.Rows.Clear();    _dgvSumRow.Rows.Add(1);  }  if (this.Rows.Count <= 0 || SumColumns == null || SumColumns.Length == 0)  {    return;  }  var sumRowDataDic = new Dictionary<int, decimal>();  #region 按设置的需要合计的列求和  Array.ForEach(SumColumns, col =>  {    if (!_dgvSumRow.Columns.Contains(col))    {      return;    }    var tempSumVal = 0m;    var colIndex = _dgvSumRow.Columns[col].Index;    for (int i = 0; i < this.Rows.Count; i++)    {      if (this[colIndex, i].Value == null)      {        continue;      }      var tempVal = 0m;      try      {        tempVal = (decimal)Convert.ChangeType(this[colIndex, i].Value, typeof(decimal));      }      catch { }      tempSumVal += tempVal;    }    sumRowDataDic[colIndex] = tempSumVal;  });  #endregion  if (sumRowDataDic.Count > 0)  {    sumRowDataDic.Keys.ToList().ForEach(colIndex =>    {      _dgvSumRow[colIndex, 0].Value = sumRowDataDic[colIndex];    });  }}/// <summary>/// 获取合计行/// </summary>[Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]public DataGridViewRow SumRow{  get  {    return (_isShowSumRow && _dgvSumRow.Rows.Count > 0) ? _dgvSumRow.Rows[0] : null;  }}

  9. 当数据源改变,重新计算合计,与合计行列头重绘
    private void this_DataSourceChanged(object sender, EventArgs e){  SumData();}/// <summary>/// 绘制合计行行头/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void dgvSumRow_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e){  var rectangle = new Rectangle(e.RowBounds.Location.X + 1, e.RowBounds.Location.Y + 1,    _dgvSumRow.RowHeadersWidth - 3, e.RowBounds.Height - 3);  e.Graphics.FillRectangle(new SolidBrush(_dgvSumRow.RowHeadersDefaultCellStyle.BackColor), rectangle);  TextRenderer.DrawText(e.Graphics, "合计",    _dgvSumRow.RowHeadersDefaultCellStyle.Font,    rectangle,    _dgvSumRow.RowHeadersDefaultCellStyle.ForeColor,    TextFormatFlags.VerticalCenter | TextFormatFlags.HorizontalCenter);}

  10. 为了便于在设计器中使用,重写部分属性,并禁用可能影响展示效果的属性,同时增加上新的属性设置.
    /// <summary>/// 获取或设置Dock,该属性已被重新/// </summary>[Description("获取或设置Dock,该属性已被重写")]public new DockStyle Dock{  get { return _dock; }  set  {    _dock = value;    if (value == DockStyle.Fill)    {      if (Parent != null)      {        this.Size = new Size(Parent.Width, Parent.Height);        this.Location = new Point(0, 0);      }      this.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;    }    else    {      this.Height = Parent.Height - 20;      this.Width = Parent.Width - 20;    }  }}/// <summary>/// BorderStyle属性已被重写,该值固定为None,设置无效/// </summary>[Description("BorderStyle属性已被重写,该值固定为None,设置无效")]public new BorderStyle BorderStyle{  get { return System.Windows.Forms.BorderStyle.None; }  set { }}/// <summary>/// 获取或设置合计行单元格格式化字符串/// </summary>[Description("获取或设置合计行单元格格式化字符串")]public string SumRowCellFormat{  get { return _sumCellFormat; }  set { _sumCellFormat = value; }}/// <summary>/// 获取或设置是否显示合计行/// </summary>[Description("获取或设置是否显示合计行")]public bool IsShowSumRow{  get { return _isShowSumRow; }  set  {    _isShowSumRow = value;    InitScrollWithSourceGrid();  }}

 

后记,以上就是为DataGridView增加合计行功能扩展的关键代码,还望能帮助到有类似需求的朋友,或许本文于你的帮助仅为一个思路,并不完全代表你必须像我这么处理,各位看官还望斟酌.

另外本文不提供直接源码包下载,因为感觉如果你真的想学习还是自己这部分代码可能比较直接,直接复制文件的这种形式,估计能学到的可能性也比较小.希望直接获取源码包的朋友请绕道,还望见谅.