Question

我想通过 iTextSharp库将数据从 DataGridView 导出到 PDF文件。

但是当我点击导出Pdf 时会出现此错误。

对象引用未设置为对象的实例。

线路错误：

//fetch the header text
cellText = Server.HtmlDecode(gvProducts.HeaderRow.Cells[colIndex].Text);

我有这个问题，只有变量rowCountProducts等于零。

有人能帮助我吗？

提前致谢代码如下。

if (rowCountProducts >= 0)
{
    //link button column is excluded from the list
    int colCount = gvProducts.Columns.Count - 1;

    //Create a table
    table = new PdfPTable(colCount);
    table.HorizontalAlignment = 1;
    table.WidthPercentage = 100;

    //create an array to store column widths
    int[] colWidths = new int[gvProducts.Columns.Count];

    PdfPCell cell;
    string cellText;

        //create the header row
        for (int colIndex = 0; colIndex < colCount; colIndex++)
        {
            //set the column width
            table.SetWidths(new int[] { 0, 15, 15, 20, 20, 15, 8, 12, 20, 20, 10, 12, 10, 20, 12, 10, 10, 12, 30, 8, 12, 12, 10 });


            //fetch the header text
            cellText = Server.HtmlDecode(gvProducts.HeaderRow.Cells[colIndex].Text);

            //create a new cell with header text
            BaseFont bf = BaseFont.CreateFont(
                                    BaseFont.HELVETICA,
                                    BaseFont.CP1252,
                                    BaseFont.EMBEDDED,
                                    false);
            iTextSharp.text.Font font = new iTextSharp.text.Font(bf, 10, iTextSharp.text.Font.BOLD, BaseColor.WHITE);
            cell = new PdfPCell(new Phrase(cellText.Replace("<br />", Environment.NewLine), font));
            cell.HorizontalAlignment = Element.ALIGN_CENTER;
            cell.VerticalAlignment = Element.ALIGN_MIDDLE;
            cell.FixedHeight = 55f;

            //set the background color for the header cell
            cell.BackgroundColor = new BaseColor(System.Drawing.ColorTranslator.FromHtml("#a52a2a"));

            //add the cell to the table. we dont need to create a row and add cells to the row
            //since we set the column count of the table to 4, it will automatically create row for
            //every 4 cells
            table.AddCell(cell);
        }

    //export rows from GridView to table
    for (int rowIndex = 0; rowIndex < gvProducts.Rows.Count; rowIndex++)
    {
        if (gvProducts.Rows[rowIndex].RowType == DataControlRowType.DataRow)
        {
            for (int j = 0; j < gvProducts.Columns.Count - 1; j++)
            {
                //fetch the column value of the current row
                cellText = Server.HtmlDecode(gvProducts.Rows[rowIndex].Cells[j].Text);

                //create a new cell with column value
                cell = new PdfPCell(new Phrase(cellText, FontFactory.GetFont("PrepareForExport", 8)));
                cell.HorizontalAlignment = Element.ALIGN_CENTER;
                cell.VerticalAlignment = Element.ALIGN_MIDDLE;
                cell.FixedHeight = 55f;

                string cellText2 = Server.HtmlDecode(gvProducts.Rows[rowIndex].Cells[6].Text);

                if (cellText2.ToString() == "B")
                {
                    cell.BackgroundColor = new BaseColor(System.Drawing.ColorTranslator.FromHtml("#f5f5dc"));
                }
                if (cellText2.ToString() == "L")
                {
                    cell.BackgroundColor = new BaseColor(System.Drawing.ColorTranslator.FromHtml("#dcf5f5"));
                }
                if (cellText2.ToString() == "T")
                {
                    cell.BackgroundColor = new BaseColor(System.Drawing.ColorTranslator.FromHtml("#ffe9de"));
                }

                //add the cell to the table
                table.AddCell(cell);
            }
        }
    }
}

Answer 1

如果你的问题是

rowCountProducts

等于零，请尝试这个。

我希望这有帮助。

//fetch the header text
//start
if (rowCountProducts > 0)
{
    cellText = Server.HtmlDecode(gvProducts.HeaderRow.Cells[colIndex].Text);
}
else
{
    cellText = "";
}
//end

iTextSharp错误对象引用未设置为对象的实例

1 个答案: