NPOI 生成Excel （单元格合并、设置单元格样式：字段，颜色、设置单元格为下拉框并限制输入值、设置单元格只能输入数字等）

NPIO源码地址：https://github.com/tonyqus/npoi

NPIO使用参考：源码中的 NPOITest项目

下面代码包括：

1、包含多个Sheet的Excel

2、单元格合并

3、设置单元格样式：字段，颜色

4、设置单元格为下拉框并限制输入值

5、设置单元格只能输入数字

//
// GET: /Excel/
public ActionResult Write()
{
var workbook = new HSSFWorkbook();//从流内容创建Workbook对象
ISheet sheet = ((HSSFWorkbook)workbook).CreateSheet("sheetOne");//创建工作表

IRow row = sheet.CreateRow(0);//在工作表中添加一行
ICell cell = row.CreateCell(1);//在行中添加一列
cell.SetCellValue("test");//设置列的内容
setCellStyle(workbook, cell);
mergeCell(sheet, 0, 0, 1, 4);

sheet = ((HSSFWorkbook)workbook).CreateSheet("sheet2");//创建工作表
setCellDropdownlist(sheet);
setCellInputNumber(sheet);

string filePath = Server.MapPath("~/ExportFiles/test.xls");
FileStream fs = new FileStream(filePath, FileMode.Create);
workbook.Write(fs);
fs.Close();

return null;
}

/// <summary>
/// 设置单元格为下拉框并限制输入值
/// </summary>
/// <param name="sheet"></param>
private void setCellDropdownlist(ISheet sheet)
{
//设置生成下拉框的行和列
var cellRegions = new CellRangeAddressList(0, 65535, 0, 0);

//设置 下拉框内容
DVConstraint constraint = DVConstraint.CreateExplicitListConstraint(
new string[] { "itemA", "itemB", "itemC" });

//绑定下拉框和作用区域，并设置错误提示信息
HSSFDataValidation dataValidate = new HSSFDataValidation(cellRegions, constraint);
dataValidate.CreateErrorBox("输入不合法", "请输入下拉列表中的值。");
dataValidate.ShowPromptBox = true;

sheet.AddValidationData(dataValidate);
}

/// <summary>
/// 设置单元格只能输入数字
/// </summary>
/// <param name="sheet"></param>
private void setCellInputNumber(ISheet sheet)
{
//设置生成下拉框的行和列
var cellRegions = new CellRangeAddressList(0, 65535, 1, 1);

//第二个参数int comparisonOperator  参考源码获取
//https://github.com/tonyqus/npoi
//NPOITest项目
DVConstraint constraint = DVConstraint.CreateNumericConstraint(
ValidationType.INTEGER, OperatorType.BETWEEN, "0", "100");

HSSFDataValidation dataValidate = new HSSFDataValidation(cellRegions, constraint);
dataValidate.CreateErrorBox("输入不合法", "请输入1~100的数字。");
//dataValidate.PromptBoxTitle = "ErrorInput";

sheet.AddValidationData(dataValidate);
}

/// <summary>
/// 合并单元格
/// </summary>
/// <param name="sheet"></param>
/// <param name="firstRow"></param>
/// <param name="lastRow"></param>
/// <param name="firstCell"></param>
/// <param name="lastCell"></param>
private void mergeCell(ISheet sheet, int firstRow, int lastRow, int firstCell, int lastCell)
{
sheet.AddMergedRegion(new CellRangeAddress(firstRow, lastRow, firstCell, lastCell));//2.0使用 2.0以下为Region
}

/// <summary>
/// 设置单元格样式
/// </summary>
/// <param name="workbook"></param>
/// <param name="cell"></param>
private void setCellStyle(HSSFWorkbook workbook, ICell cell)
{
HSSFCellStyle fCellStyle = (HSSFCellStyle)workbook.CreateCellStyle();
HSSFFont ffont = (HSSFFont)workbook.CreateFont();
ffont.FontHeight = 20 * 20;
ffont.FontName = "宋体";
ffont.Color = HSSFColor.Red.Index;
fCellStyle.SetFont(ffont);

fCellStyle.VerticalAlignment = NPOI.SS.UserModel.VerticalAlignment.Center;//垂直对齐
fCellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;//水平对齐
cell.CellStyle = fCellStyle;
}