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  • 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.
      imageimageimage
    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grid
private DockStyle _dock;                        //Dock

private 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.
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  • 原文地址：https://www.cnblogs.com/xie-zhonglai/p/data_grid_view_sum_row.html
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