使用C#和Excel进行报表开发－生成统计图Chart

    原文地址：http://www.opent.cn/a/094/1235.shtml

    有的Web项目选用Excel作为报表方案，在服务器端生成Excel文件，然后传送到客户端，由客户端进行打印。在国内的环境下，相对PDF方式，Excel的安装率应该比pdf阅读器的安装率要高，同时，微软也为C#操作Excel提供了完备的接口，虽然ZedGraph和其他的商业报表工具生成的统计图也很好，但是人家微软毕竟是大品牌，值得信赖。

    本文进一步演示如何从指定的数据从头生成统

    首先当然要添加对Excel的引用，然后需要定义几个要用到的Excel对象

Excel.Application ThisApplication = null;
Excel.Workbooks m_objBooks = null;
Excel._Workbook ThisWorkbook = null;
Excel.Worksheet xlSheet = null;

在创建一个新的_WorkBook对象的时候，默认的会含有3个Sheet，所以为了显示清晰，将多余的Sheet都删掉：

private void DeleteSheet()
{
        foreach (Excel.Worksheet ws in ThisWorkbook.Worksheets)
                if (ws != ThisApplication.ActiveSheet)
                {
                        ws.Delete();
                }
        foreach (Excel.Chart cht in ThisWorkbook.Charts)
                cht.Delete();
                        
}

再下来需要添加用来给Chart提供数据的Sheet：

private void AddDatasheet()
{
        xlSheet = (Excel.Worksheet)ThisWorkbook.
                Worksheets.Add(Type.Missing, ThisWorkbook.ActiveSheet,
                Type.Missing, Type.Missing);
 
        xlSheet.Name = "数据";
}

生成Chart用到的数据，因为是演示，所以这里使用生成随机数的方法来替代从数据库中提取数据。

private void LoadData()
{
        Random ran = new Random();
        for (int i = 1; i <= 12; i++)
        {
                xlSheet.Cells[i,  1] = i.ToString() + "月";
                xlSheet.Cells[i, 2] = ran.Next(2000).ToString();        
        }
}

好了，到此，准备工作全部已经就绪，下面要进行Chart的生成设置部分了：

生成一个统计图对象：

Excel.Chart xlChart = (Excel.Chart)ThisWorkbook.Charts.
                Add(Type.Missing, xlSheet, Type.Missing, Type.Missing);

设定数据来源：

Excel.Range cellRange = (Excel.Range)xlSheet.Cells[1, 1];

通过向导生成Chart：

xlChart.ChartWizard(cellRange.CurrentRegion,
                Excel.XlChartType.xl3DColumn, Type.Missing,
                Excel.XlRowCol.xlColumns,1, 0, true ,
                "访问量比较(dahuzizyd.cnblogs.com)", "月份", "访问量",
                "");

到此，Chart的生成就完成了，貌似比较简单，下面我们对其作一些设置，好更漂亮些。
设置统计图Sheet的名称：
xlChart.Name = "统计";
 
现在的统计图只有一个组，他们会显示成一样的颜色，我们来让12个Bar都显示不同的颜色：

Excel.ChartGroup grp = (Excel.ChartGroup)xlChart.ChartGroups(1);
grp.GapWidth = 20;
grp.VaryByCategories = true;

现在Chart的条目的显示形状是Box，我们让它们变成圆柱形，并给它们显示加上数据标签：

Excel.Series s = (Excel.Series)grp.SeriesCollection(1);
s.BarShape = XlBarShape.xlCylinder;
s.HasDataLabels = true;

下面再来设置统计图的标题和图例的显示：

xlChart.Legend.Position = XlLegendPosition.xlLegendPositionTop;
xlChart.ChartTitle.Font.Size = 24;
xlChart.ChartTitle.Shadow = true;
xlChart.ChartTitle.Border.LineStyle = Excel.XlLineStyle.xlContinuous;

最后设置两个轴的属性，Excel.XlAxisType.xlValue对应的是Y轴，Excel.XlAxisType.xlCategory对应的是X轴：

Excel.Axis valueAxis = (Excel.Axis)xlChart.Axes(Excel.XlAxisType.xlValue, XlAxisGroup.xlPrimary);
valueAxis.AxisTitle.Orientation = -90;
 
Excel.Axis categoryAxis = (Excel.Axis)xlChart.Axes(Excel.XlAxisType.xlCategory, XlAxisGroup.xlPrimary);
categoryAxis.AxisTitle.Font.Name = "MS UI Gothic";
 

到此，一切就绪了，下面要生成Chart，并将其存为一个Excel文件：

private void button4_Click(object sender, EventArgs e)
{
    try
    {
        ThisApplication = new Excel.Application();
        m_objBooks = (Excel.Workbooks)ThisApplication.Workbooks;
        ThisWorkbook = (Excel._Workbook)(m_objBooks.Add(Type.Missing));

        ThisApplication.DisplayAlerts = false;

        this.DeleteSheet();
        this.AddDatasheet();
        this.LoadData();

        CreateChart();

        ThisWorkbook.SaveAs("z:\\Book2.xls", Type.Missing, Type.Missing,
                    Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlNoChange,
                Type.Missing, Type.Missing, Type.Missing, Type.Missing);

    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
    finally
    {
        ThisWorkbook.Close(Type.Missing, Type.Missing, Type.Missing);
        ThisApplication.Workbooks.Close();

        ThisApplication.Quit();
                System.Runtime.InteropServices.Marshal.ReleaseComObject(ThisWorkbook);
                System.Runtime.InteropServices.Marshal.ReleaseComObject(ThisApplication);
        ThisWorkbook = null;
        ThisApplication = null;
        GC.Collect();
        this.Close();
    }

}

Excel.Application ThisApplication = null;
Excel.Workbooks m_objBooks = null;
Excel._Workbook ThisWorkbook = null;

Excel.Worksheet xlSheet = null;

/**//// 
/// 用生成的随机数作数据
/// 
private void LoadData()
{
    Random ran = new Random();
    for (int i = 1; i <= 12; i++)
    {
        xlSheet.Cells[i,  1] = i.ToString() + "月";
        xlSheet.Cells[i, 2] = ran.Next(2000).ToString();    
    }
}
/**//// 
/// 删除多余的Sheet
/// 
private void DeleteSheet()
{
    foreach (Excel.Worksheet ws in ThisWorkbook.Worksheets)
        if (ws != ThisApplication.ActiveSheet)
        {
            ws.Delete();
        }
    foreach (Excel.Chart cht in ThisWorkbook.Charts)
        cht.Delete();
            
}
/**//// 
/// 创建一个Sheet，用来存数据
/// 
private void AddDatasheet()
{
    xlSheet = (Excel.Worksheet)ThisWorkbook.
        Worksheets.Add(Type.Missing, ThisWorkbook.ActiveSheet,
        Type.Missing, Type.Missing);

    xlSheet.Name = "数据";
}
/**//// 
/// 创建统计图         
/// 
private void CreateChart()
{
    Excel.Chart xlChart = (Excel.Chart)ThisWorkbook.Charts.
        Add(Type.Missing, xlSheet, Type.Missing, Type.Missing);

    Excel.Range cellRange = (Excel.Range)xlSheet.Cells[1, 1];
    xlChart.ChartWizard(cellRange.CurrentRegion,
        Excel.XlChartType.xl3DColumn, Type.Missing,
        Excel.XlRowCol.xlColumns,1, 0, true ,
        "访问量比较(dahuzizyd.cnblogs.com)", "月份", "访问量",
        "");

    xlChart.Name = "统计";

    Excel.ChartGroup grp = (Excel.ChartGroup)xlChart.ChartGroups(1);
    grp.GapWidth = 20;
    grp.VaryByCategories = true;

    Excel.Series s = (Excel.Series)grp.SeriesCollection(1);
    s.BarShape = XlBarShape.xlCylinder;
    s.HasDataLabels = true;

    xlChart.Legend.Position = XlLegendPosition.xlLegendPositionTop;
    xlChart.ChartTitle.Font.Size = 24;
    xlChart.ChartTitle.Shadow = true;
    xlChart.ChartTitle.Border.LineStyle = Excel.XlLineStyle.xlContinuous;
            
    Excel.Axis valueAxis = (Excel.Axis)xlChart.Axes(Excel.XlAxisType.xlValue, XlAxisGroup.xlPrimary);
    valueAxis.AxisTitle.Orientation = -90;

    Excel.Axis categoryAxis = (Excel.Axis)xlChart.Axes(Excel.XlAxisType.xlCategory, XlAxisGroup.xlPrimary);
    categoryAxis.AxisTitle.Font.Name = "MS UI Gothic";
}
try
{
    ThisApplication = new Excel.Application();
    m_objBooks = (Excel.Workbooks)ThisApplication.Workbooks;
    ThisWorkbook = (Excel._Workbook)(m_objBooks.Add(Type.Missing));

    ThisApplication.DisplayAlerts = false;

    this.DeleteSheet();
    this.AddDatasheet();
    this.LoadData();

    CreateChart();

    ThisWorkbook.SaveAs("z:\\Book2.xls", Type.Missing, Type.Missing,
                    Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlNoChange,
                Type.Missing, Type.Missing, Type.Missing, Type.Missing);

}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}
finally
{
    ThisWorkbook.Close(Type.Missing, Type.Missing, Type.Missing);
    ThisApplication.Workbooks.Close();

    ThisApplication.Quit();
            System.Runtime.InteropServices.Marshal.ReleaseComObject(ThisWorkbook);
                System.Runtime.InteropServices.Marshal.ReleaseComObject(ThisApplication);
    ThisWorkbook = null;
    ThisApplication = null;
    GC.Collect();
    this.Close();
}

运行你的程序，打开生成的Excel文件，最终生成的Chart应该像这样：

完成了Chart的生成，但是上面对于每个月只有一项数据，如果我想显示多项呢，例如显示每个月两个页面的范围量的对比。方法很简单，只要再多生成一组数据就可以了，我们修改下LoadData方法：

private void LoadData()
{
        Random ran = new Random();
        for (int i = 1; i <= 12; i++)
        {
                xlSheet.Cells[i,  1] = i.ToString() + "月";
                xlSheet.Cells[i, 2] = ran.Next(2000).ToString();
xlSheet.Cells[i, 3] = ran.Next(1500).ToString();        
        }
} 

再次运行程序，生成Chart看看，应该像下面的效果:

可以看到，两组数据以不同的形状显示，同时，图例部分也不再显示1－12月共12项，而是显示两项，这是因为在上面的代码中我们设置了ChartGroup的VaryByCategories 属性：
grp.VaryByCategories = true;当我们有两个以上的组时，这一项就失效了。
 
在用C#操作Excel的时候，恐怕最大的困难就在于不知道Excel提供的各个对象，以及它们的属性，方法等信息，好在MSDN里有关于Excel的接口说明－Excel Primary Interop Assembly Reference，参照这些，相信很快就能上手了。