C# NPOI使用

 HSSFWorkbook workbook = new HSSFWorkbook();
 HSSFSheet sheet = workbook.CreateSheet( "Sheet1") as HSSFSheet;
 IRow row = sheet.CreateRow();
     row.Height =  * ;

 ICell cellTitle = row.CreateCell();
     titleHeader.Alignment = HorizontalAlignment.Center;
     titleHeader.VerticalAlignment = VerticalAlignment.Center;

         style.BorderBottom = BorderStyle.Thin;
         style.BorderLeft = BorderStyle.Thin;
         style.BorderRight = BorderStyle.Thin;

 IFont font = workbook.CreateFont();
     font.FontHeightInPoints = ;
     font.FontName = "微软雅黑";
         font.IsBold = true;

 cellTitle.SetFont(font);
 cellTitle.SetCellValue(titleName)

 Color c = Color.FromArgb(, , );
                 HSSFPalette palette = workbook.GetCustomPalette();
                 palette.SetColorAtIndex((short), c.R, c.G, c.B);
                 HSSFColor cellColor = palette.FindColor(c.R, c.G, c.B);
 style.FillPattern = FillPattern.SolidForeground;
 style.FillForegroundColor = cellColor.Indexed;

 region = new CellRangeAddress(, , , columnsCount - );
 sheet.AddMergedRegion(region);
 ((HSSFSheet)sheet).SetEnclosedBorderOfRegion(region, BorderStyle.Thin, HSSFColor.Black.Index);

    //列宽自适应，只对英文和数字有效
                 for (int i = ; i <= columnsCount; i++)
                 {
                     sheet.AutoSizeColumn(i);
                 }

                 //列宽自适应中文有效
                 for (int i = ; i < ; i++)
                 {
                     int columnWidth = sheet.GetColumnWidth(i) / ;
                     for (int rowNum = ; rowNum <  + rowsCount; rowNum++)
                     {
                         IRow currentRow;
                         //当前行未被使用过
                         if (sheet.GetRow(rowNum) == null)
                         {
                             currentRow = sheet.CreateRow(rowNum);
                         }
                         else
                         {
                             currentRow = sheet.GetRow(rowNum);
                         }

                         if (currentRow.GetCell(i) != null)
                         {
                             ICell currentCell = currentRow.GetCell(i);
                             int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;
                             if (columnWidth < length)
                             {
                                 columnWidth = length;
                             }
                         }
                     }
                     sheet.SetColumnWidth(i, columnWidth * );
                 }

                 //列宽自适应中文有效
                 for (int i = ; i < columnsCount; i++)
                 {
                     int rowNum;

                     if (dtSource.Columns[i].ColumnName.Contains("/"))
                     {
                         rowNum = ;
                     }
                     else
                     {
                         rowNum = ;
                     }

                     int columnWidth = sheet.GetColumnWidth(i) / ;
                     for (; rowNum <  + rowsCount; rowNum++)
                     {
                         IRow currentRow;
                         //当前行未被使用过
                         if (sheet.GetRow(rowNum) == null)
                         {
                             currentRow = sheet.CreateRow(rowNum);
                         }
                         else
                         {
                             currentRow = sheet.GetRow(rowNum);
                         }

                         if (currentRow.GetCell(i) != null)
                         {
                             ICell currentCell = currentRow.GetCell(i);
                             int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;
                             if (columnWidth < length)
                             {
                                 columnWidth = length;
                             }
                         }
                     }
                     sheet.SetColumnWidth(i, columnWidth * );
                 }

  //若没有数据则建立空文档
             if (workbook.NumberOfSheets == )
             {
                 HSSFSheet sheet = workbook.CreateSheet("Sheet1") as HSSFSheet;
             }

   //写文件
             MemoryStream ms = new MemoryStream();
             workbook.Write(ms);
             ms.Flush();
             ms.Seek(, SeekOrigin.Begin); //ms.Position = 0;

     return ms;

    if (j ==  )
     {
     double db = ;
     if (double.TryParse(objVal.ToString(), out db))
     {
         cell.SetCellValue(db);
     }
     }
     else
     {
     SetCellValue(cell, objVal);
     }

 public static void SetCellValue(ICell eCell, object data)
 {
     string typeStr = data.GetType().ToString();

     switch (typeStr)
     {
         case "System.String":
             eCell.SetCellValue(data.ToString());
             break;
         case "System.DateTime":
             System.DateTime dateV;
             System.DateTime.TryParse(data.ToString(), out dateV);
             eCell.SetCellValue(dateV.ToString("yyyy/MM/dd"));
             break;
         case "System.Boolean":
             bool boolV = false;
             bool.TryParse(data.ToString(), out boolV);
             eCell.SetCellValue(boolV);
             break;
         case "System.Int16":
         case "System.Int32":
         case "System.Int64":
         case "System.Byte":
             int intV = ;
             int.TryParse(data.ToString(), out intV);
             eCell.SetCellValue(intV);
             break;
         case "System.Decimal":
         case "System.Double":
             double doubV = ;
             double.TryParse(data.ToString(), out doubV);
             eCell.SetCellValue(doubV);
             break;
         case "System.DBNull":
             eCell.SetCellValue("");
             break;
         default:
             eCell.SetCellValue("");
             break;
     }
 }

HSSFWorkbook workbook = new HSSFWorkbook();

HSSFSheet sheet = workbook.CreateSheet( "Sheet1") as HSSFSheet;

IRow row = sheet.CreateRow();

    row.Height = * ;

ICell cellTitle = row.CreateCell();

    titleHeader.Alignment = HorizontalAlignment.Center;

    titleHeader.VerticalAlignment = VerticalAlignment.Center;

    

style.BorderBottom = BorderStyle.Thin;

style.BorderLeft = BorderStyle.Thin;

style.BorderRight = BorderStyle.Thin;

IFont font = workbook.CreateFont();

    font.FontHeightInPoints = ;

    font.FontName = "微软雅黑";

font.IsBold = true;

cellTitle.SetFont(font);

cellTitle.SetCellValue(titleName)

Color c = Color.FromArgb(, , );

HSSFPalette palette = workbook.GetCustomPalette();

palette.SetColorAtIndex((short), c.R, c.G, c.B);

HSSFColor cellColor = palette.FindColor(c.R, c.G, c.B);

style.FillPattern = FillPattern.SolidForeground;

style.FillForegroundColor = cellColor.Indexed;

region = new CellRangeAddress(, , , columnsCount - );

sheet.AddMergedRegion(region);

((HSSFSheet)sheet).SetEnclosedBorderOfRegion(region, BorderStyle.Thin, HSSFColor.Black.Index);

//列宽自适应，只对英文和数字有效

for (int i = ; i <= columnsCount; i++)

{

sheet.AutoSizeColumn(i);

}

//列宽自适应中文有效

for (int i = ; i < ; i++)

{

int columnWidth = sheet.GetColumnWidth(i) / ;

for (int rowNum = ; rowNum < + rowsCount; rowNum++)

{

IRow currentRow;

//当前行未被使用过

if (sheet.GetRow(rowNum) == null)

{

currentRow = sheet.CreateRow(rowNum);

}

else

{

currentRow = sheet.GetRow(rowNum);

}

if (currentRow.GetCell(i) != null)

{

ICell currentCell = currentRow.GetCell(i);

int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;

if (columnWidth < length)

{

columnWidth = length;

}

}

}

sheet.SetColumnWidth(i, columnWidth * );

}

//列宽自适应中文有效

for (int i = ; i < columnsCount; i++)

{

int rowNum;

if (dtSource.Columns[i].ColumnName.Contains("/"))

{

rowNum = ;

}

else

{

rowNum = ;

}

int columnWidth = sheet.GetColumnWidth(i) / ;

for (; rowNum < + rowsCount; rowNum++)

{

IRow currentRow;

//当前行未被使用过

if (sheet.GetRow(rowNum) == null)

{

currentRow = sheet.CreateRow(rowNum);

}

else

{

currentRow = sheet.GetRow(rowNum);

}

if (currentRow.GetCell(i) != null)

{

ICell currentCell = currentRow.GetCell(i);

int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;

if (columnWidth < length)

{

columnWidth = length;

}

}

}

sheet.SetColumnWidth(i, columnWidth * );

}

//若没有数据则建立空文档

if (workbook.NumberOfSheets == )

{

HSSFSheet sheet = workbook.CreateSheet("Sheet1") as HSSFSheet;

}

//写文件

MemoryStream ms = new MemoryStream();

workbook.Write(ms);

ms.Flush();

ms.Seek(, SeekOrigin.Begin); //ms.Position = 0;

return ms;

if (j == )

{

double db = ;

if (double.TryParse(objVal.ToString(), out db))

{

cell.SetCellValue(db);

}

}

else

{

SetCellValue(cell, objVal);

}

public static void SetCellValue(ICell eCell, object data)

{

string typeStr = data.GetType().ToString();

switch (typeStr)

{

case "System.String":

eCell.SetCellValue(data.ToString());

break;

case "System.DateTime":

System.DateTime dateV;

System.DateTime.TryParse(data.ToString(), out dateV);

eCell.SetCellValue(dateV.ToString("yyyy/MM/dd"));

break;

case "System.Boolean":

bool boolV = false;

bool.TryParse(data.ToString(), out boolV);

eCell.SetCellValue(boolV);

break;

case "System.Int16":

case "System.Int32":

case "System.Int64":

case "System.Byte":

int intV = ;

int.TryParse(data.ToString(), out intV);

eCell.SetCellValue(intV);

break;

case "System.Decimal":

case "System.Double":

double doubV = ;

double.TryParse(data.ToString(), out doubV);

eCell.SetCellValue(doubV);

break;

case "System.DBNull":

eCell.SetCellValue("");

break;

default:

eCell.SetCellValue("");

break;

}

}