C# programming Excel import and export (source code download) (Part 2)

/// <summary>
/// 实体类集合导出到Excle2003
/// </summary>
/// <param name="cellHeard">单元头的Key和Value：{ { "UserName", "姓名" }, { "Age", "年龄" } };</param>
/// <param name="enList">数据源</param>
/// <param name="sheetName">工作表名称</param>
/// <returns>文件的下载地址</returns>
public static string EntityListToExcel2003(Dictionary<string, string> cellHeard, IList enList, string sheetName)
{
    try
    {
        string fileName = sheetName + "-" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".xls"; // 文件名称
        string urlPath = "UpFiles/ExcelFiles/" + fileName; // 文件下载的URL地址，供给前台下载
        string filePath = HttpContext.Current.Server.MapPath("\\" + urlPath); // 文件路径
 
        // 1.检测是否存在文件夹，若不存在就建立个文件夹
        string directoryName = Path.GetDirectoryName(filePath);
        if (!Directory.Exists(directoryName))
        {
            Directory.CreateDirectory(directoryName);
        }
 
        // 2.解析单元格头部，设置单元头的中文名称
        HSSFWorkbook workbook = new HSSFWorkbook(); // 工作簿
        ISheet sheet = workbook.CreateSheet(sheetName); // 工作表
        IRow row = sheet.CreateRow(0);
        List<string> keys = cellHeard.Keys.ToList();
        for (int i = 0; i < keys.Count; i++)
        {
            row.CreateCell(i).SetCellValue(cellHeard[keys[i]]); // 列名为Key的值
        }
 
        // 3.List对象的值赋值到Excel的单元格里
        int rowIndex = 1; // 从第二行开始赋值(第一行已设置为单元头)
        foreach (var en in enList)
        {
            IRow rowTmp = sheet.CreateRow(rowIndex);
            for (int i = 0; i < keys.Count; i++) // 根据指定的属性名称，获取对象指定属性的值
            {
                string cellValue = ""; // 单元格的值
                object properotyValue = null; // 属性的值
                System.Reflection.PropertyInfo properotyInfo = null; // 属性的信息
 
                // 3.1 若属性头的名称包含&#39;.&#39;,就表示是子类里的属性，那么就要遍历子类，eg：UserEn.UserName
                if (keys[i].IndexOf(".") >= 0)
                {
                    // 3.1.1 解析子类属性(这里只解析1层子类，多层子类未处理)
                    string[] properotyArray = keys[i].Split(new string[] { "." }, StringSplitOptions.RemoveEmptyEntries);
                    string subClassName = properotyArray[0]; // &#39;.&#39;前面的为子类的名称
                    string subClassProperotyName = properotyArray[1]; // &#39;.&#39;后面的为子类的属性名称
                    System.Reflection.PropertyInfo subClassInfo = en.GetType().GetProperty(subClassName); // 获取子类的类型
                    if (subClassInfo != null)
                    {
                        // 3.1.2 获取子类的实例
                        var subClassEn = en.GetType().GetProperty(subClassName).GetValue(en, null);
                        // 3.1.3 根据属性名称获取子类里的属性类型
                        properotyInfo = subClassInfo.PropertyType.GetProperty(subClassProperotyName);
                        if (properotyInfo != null)
                        {
                            properotyValue = properotyInfo.GetValue(subClassEn, null); // 获取子类属性的值
                        }
                    }
                }
                else
                {
                    // 3.2 若不是子类的属性，直接根据属性名称获取对象对应的属性
                    properotyInfo = en.GetType().GetProperty(keys[i]);
                    if (properotyInfo != null)
                    {
                        properotyValue = properotyInfo.GetValue(en, null);
                    }
                }
 
                // 3.3 属性值经过转换赋值给单元格值
                if (properotyValue != null)
                {
                    cellValue = properotyValue.ToString();
                    // 3.3.1 对时间初始值赋值为空
                    if (cellValue.Trim() == "0001/1/1 0:00:00" || cellValue.Trim() == "0001/1/1 23:59:59")
                    {
                        cellValue = "";
                    }
                }
 
                // 3.4 填充到Excel的单元格里
                rowTmp.CreateCell(i).SetCellValue(cellValue);
            }
            rowIndex++;
        }
 
        // 4.生成文件
        FileStream file = new FileStream(filePath, FileMode.Create);
        workbook.Write(file);
        file.Close();
 
        // 5.返回下载路径
        return urlPath;
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

public void ExportExcel(HttpContext context)
{
    try
    {
        // 1.获取数据集合
        List<UserEntity> enlist = new List<UserEntity>() {
            new UserEntity{Name="刘一",Age=22,Gender="Male",TranscriptsEn=new TranscriptsEntity{ChineseScores=80,MathScores=90}},
            new UserEntity{Name="陈二",Age=23,Gender="Male",TranscriptsEn=new TranscriptsEntity{ChineseScores=81,MathScores=91} },
            new UserEntity{Name="张三",Age=24,Gender="Male",TranscriptsEn=new TranscriptsEntity{ChineseScores=82,MathScores=92} },
            new UserEntity{Name="李四",Age=25,Gender="Male",TranscriptsEn=new TranscriptsEntity{ChineseScores=83,MathScores=93} },
            new UserEntity{Name="王五",Age=26,Gender="Male",TranscriptsEn=new TranscriptsEntity{ChineseScores=84,MathScores=94} },
        };
 
        // 2.设置单元格抬头
        // key：实体对象属性名称，可通过反射获取值
        // value：Excel列的名称
        Dictionary<string, string> cellheader = new Dictionary<string, string> {
            { "Name", "姓名" },
            { "Age", "年龄" },
            { "GenderName", "性别" },
            { "TranscriptsEn.ChineseScores", "语文成绩" },
            { "TranscriptsEn.MathScores", "数学成绩" },
        };
 
        // 3.进行Excel转换操作，并返回转换的文件下载链接
        string urlPath = ExcelHelper.EntityListToExcel2003(cellheader, enlist, "学生成绩");
        System.Web.Script.Serialization.JavaScriptSerializer js = new System.Web.Script.Serialization.JavaScriptSerializer();
        context.Response.ContentType = "text/plain";
        context.Response.Write(js.Serialize(urlPath)); // 返回Json格式的内容
    }
    catch (Exception ex)
    {
        throw ex;
    }
}