怎么将数据库数据导入excel出错 求教高手
public void CreateExcel(DataSet ds)
{
HttpResponse resp;
resp = Page.Response;
resp.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
resp.AppendHeader("Content-Disposition", "attachment;filename=filename.xls");

Response.ContentType = "application/ms-excel";

string colHeaders = "", ls_item = "";
DataTable dt = ds.Tables["0"];
DataRow[] myRow = dt.Select();
int i;
int cl = dt.Columns.Count;
for (i = 0; i < cl; i++)
{
if (i == cl - 1)
{
colHeaders += dt.Columns[i].Caption.ToString() + "\n";
}
else
{
colHeaders += dt.Columns[i].Caption.ToString() + "\t";
}
}
resp.Write(colHeaders);

foreach (DataRow row in myRow)
{
for (i = 0; i < cl; i++)
{
if (i == (cl - 1))
{
ls_item += row[i].ToString() + "\t";
}
else
{
ls_item += row[i].ToString() + "\n";
}
}
resp.Write(ls_item);
ls_item = "";
}
resp.End();

}

按钮事件--------------------------------

protected void id1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("server=WWW-37894A7821D;uid=sa;pwd=123;database=COLWAP");
con.Open();

SqlDataAdapter da = new SqlDataAdapter("select * from service_base_question_key",con);
DataSet ds = new DataSet();
da.Fill(ds, "service_base_question_key");

CreateExcel(ds);
}

为什么我点击按钮的时候会提示我“未将对象引用设置到对象的实例” 就是在 DataRow[] myRow = dt.Select();这段代码

求教高手


[解决办法]

C# code

//导出excel的公共方法    public void ExportData(DataSet ds, string xlsName)    {        try        {            XlsDocument xls = new XlsDocument();            xls.FileName = xlsName;            int rowIndex = 1;            int colIndex = 0;            DataTable table = ds.Tables[0];            Worksheet sheet = xls.Workbook.Worksheets.Add("导出资源");//状态栏标题名称            Cells cells = sheet.Cells;            foreach (DataColumn col in table.Columns)            {                colIndex++;                //sheet.Cells.AddValueCell(1,colIndex,col.ColumnName);//添加XLS标题行                cells.Add(1, colIndex, col.ColumnName.ToString());            }            foreach (DataRow row in table.Rows)            {                rowIndex++;                colIndex = 0;                foreach (DataColumn col in table.Columns)                {                    colIndex++;                    //sheet.Cells.AddValueCell(rowIndex, colIndex, row[col.ColumnName].ToString());//将数据添加到xls表格里                    //Cell cell= cells.AddValueCell(rowIndex, colIndex, Convert.ToDouble(row[col.ColumnName].ToString()));//转换为数字型                    Cell cell = cells.Add(rowIndex, colIndex, row[col.ColumnName].ToString());                    //如果你数据库里的数据都是数字的话 最好转换一下，不然导入到Excel里是以字符串形式显示。                    //cell.Font.FontFamily = FontFamilies.Roman; //字体                    //cell.Font.Bold = true; //字体为粗体                     cell.Font.Weight = FontWeight.Normal;                }            }            xls.Save(true);        }        catch        {            throw;        }    } 
 
[解决办法]
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public void CreateExcel(DataSet ds)
  {
  HttpResponse resp;
  resp = Page.Response;
  resp.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
  resp.AppendHeader("Content-Disposition"……

[解决办法]
用这段代码，直接复制过去就能用，如果导出源是GridView1的话，不是的话，你改一下。Button19是导出的按钮
  
C# code
//导出EXCEL protected void Button19_Click(object sender, EventArgs e)    {                 GridView1.AllowPaging = false;        GridView1.AllowSorting = false;        GridView1.DataBind();        ToExcel(GridView1, "aaa.xls");        GridView1.AllowPaging = true;        GridView1.AllowSorting = true;        GridView1.DataBind();    }    public override void VerifyRenderingInServerForm(Control control)    {        // Confirms that an HtmlForm control is rendered for    }    private void ToExcel(Control ctl, string FileName)    {        HttpContext.Current.Response.Charset = "UTF-8";        HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;        HttpContext.Current.Response.ContentType = "application/ms-excel";        HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + "" + FileName);        ctl.Page.EnableViewState = false;        System.IO.StringWriter tw = new System.IO.StringWriter();        HtmlTextWriter hw = new HtmlTextWriter(tw);        ctl.RenderControl(hw);        HttpContext.Current.Response.Write(tw.ToString());        HttpContext.Current.Response.End();    }