您可以使用此库创建格式良好的Excel文件：http://officehelper.codeplex.com/documentation参见以下示例：

using (ExcelHelper helper = new ExcelHelper(TEMPLATE_FILE_NAME, GENERATED_FILE_NAME))
{
    helper.Direction = ExcelHelper.DirectionType.TOP_TO_DOWN;
    helper.CurrentSheetName = "Sheet1";
    helper.CurrentPosition = new CellRef("C3");

    //the template xlsx should contains the named range "header"; use the command "insert"/"name".
    helper.InsertRange("header");

    //the template xlsx should contains the named range "sample1";
    //inside this range you should have cells with these values:
    //<name> , <value> and <comment>, which will be replaced by the values from the getSample()
    CellRangeTemplate sample1 = helper.CreateCellRangeTemplate("sample1", new List<string> {"name", "value", "comment"}); 
    helper.InsertRange(sample1, getSample());

    //you could use here other named ranges to insert new cells and call InsertRange as many times you want, 
    //it will be copied one after another;
    //even you can change direction or the current cell/sheet before you insert

    //typically you put all your "template ranges" (the names) on the same sheet and then you just delete it
    helper.DeleteSheet("Sheet3");
}        

示例如下：

private IEnumerable<List<object>> getSample()
{
    var random = new Random();

    for (int loop = 0; loop < 3000; loop++)
    {
        yield return new List<object> {"test", DateTime.Now.AddDays(random.NextDouble()*100 - 50), loop};
    }
}

OpenXML也是一个很好的选择，它有助于避免在服务器上安装MS Excel。Microsoft提供的Open XML SDK 2.0简化了操作Open XML包和包中的底层Open XML架构元素的任务。开放式XML应用程序编程接口（API）封装了开发人员在开放式XML包上执行的许多常见任务。

看看OpenXML:有助于避免在服务器上安装MS Excel的替代方案

我想知道为什么没有人建议PowerShell使用免费的ImportExcel模块；它可以轻松创建XML Excel文件（xlsx）。

从SQL Server等数据库创建Excel工作表时尤其容易。。。

您可以使用此库创建格式良好的Excel文件：http://officehelper.codeplex.com/documentation参见以下示例：

using (ExcelHelper helper = new ExcelHelper(TEMPLATE_FILE_NAME, GENERATED_FILE_NAME))
{
    helper.Direction = ExcelHelper.DirectionType.TOP_TO_DOWN;
    helper.CurrentSheetName = "Sheet1";
    helper.CurrentPosition = new CellRef("C3");

    //the template xlsx should contains the named range "header"; use the command "insert"/"name".
    helper.InsertRange("header");

    //the template xlsx should contains the named range "sample1";
    //inside this range you should have cells with these values:
    //<name> , <value> and <comment>, which will be replaced by the values from the getSample()
    CellRangeTemplate sample1 = helper.CreateCellRangeTemplate("sample1", new List<string> {"name", "value", "comment"}); 
    helper.InsertRange(sample1, getSample());

    //you could use here other named ranges to insert new cells and call InsertRange as many times you want, 
    //it will be copied one after another;
    //even you can change direction or the current cell/sheet before you insert

    //typically you put all your "template ranges" (the names) on the same sheet and then you just delete it
    helper.DeleteSheet("Sheet3");
}        

示例如下：

private IEnumerable<List<object>> getSample()
{
    var random = new Random();

    for (int loop = 0; loop < 3000; loop++)
    {
        yield return new List<object> {"test", DateTime.Now.AddDays(random.NextDouble()*100 - 50), loop};
    }
}

你可以试试我的SwiftExcel库。此库直接写入文件，因此非常高效。例如，您可以在几秒钟内写入100k行，而不占用任何内存。

下面是一个简单的用法示例：

using (var ew = new ExcelWriter("C:\\temp\\test.xlsx"))
{
    for (var row = 1; row <= 10; row++)
    {
        for (var col = 1; col <= 5; col++)
        {
            ew.Write($"row:{row}-col:{col}", col, row);
        }
    }
}

前段时间，我在NPOI上创建了一个DLL。使用它非常简单：

IList<DummyPerson> dummyPeople = new List<DummyPerson>();
//Add data to dummyPeople...
IExportEngine engine = new ExcelExportEngine();
engine.AddData(dummyPeople); 
MemoryStream memory = engine.Export();

你可以在这里阅读更多。

顺便说一句，它是100%开源的。随时使用、编辑和共享；）