C# 打印程序调用模板打印 扫描二维码没有值

Question

在程序中一句一句调试，都有值，模板也调用成功，可是打印出来的目标没有值，这是为什么？打印预览没有东西出来。

 private void btnPrint_Click(object sender, EventArgs e)
        {
            #region  打印
            if (!string.IsNullOrEmpty(txtWLBM.Text.ToString().Trim())
                && !string.IsNullOrEmpty(txtDyfs.Text.ToString().Trim()) && !string.IsNullOrEmpty(txtZsmf.Text.ToString().Trim()))
            {

                lblWarm.Text = "正在调用打印模版";
                int lengh = Convert.ToInt32(txtZsmf.Text.ToString().Trim());
                lblMessage.Text = lengh.ToString();
                string err = "";
                DataTable dtb = new DataTable();

                if (!string.IsNullOrEmpty(txtQstm.Text.ToString().Trim()))
                {
                    String wlbm = txtWLBM.Text.ToString().Trim();
                    String qstm = txtQstm.Text.ToString().Trim();
                    

                    if (wlbm.Substring(0, wlbm.Length - 1) == qstm.Substring(0, qstm.Length - 5))
                    {
                        dtb.Columns.Add("ljg", typeof(string));
                        dtb.Columns.Add("DYFS", typeof(string));
                        //dtb.Columns.Add("ZSMF", typeof(string));
                    }
                  for (int i = 1; i<= lengh; i++)
                   {
                        qstm = (long.Parse(qstm)+ 1).ToString();
                        //在范围内则打印
                        DataRow dr = dtb.NewRow();
                        dr["ljg"] = qstm;
                        dr["DYFS"] = txtDyfs.Text.ToString().Trim();
                        //dr["ZSMF"] = txtZsmf.Text.ToString().Trim();
                        dtb.Rows.Add(dr);   
                   }
                    
                }
                else {
                    dtb.Columns.Add("ljg", typeof(string));
                    dtb.Columns.Add("DYFS", typeof(string));
                    //dtb.Columns.Add("ZSMF", typeof(string));
                   for (int i = 1; i <=lengh; i++)
                    {
                        string code = "";//存放当前序号
                        int len = (i).ToString().Length;//序号的长度
                        if (len < 4)
                        {
                            for (int l = 1; l <= 4 - len; l++)
                            {
                                code = code + "0";//当前序号的零
                            }
                        }
                        code = code + (i).ToString();//当前序号
                        //在范围内则打印
                        DataRow dr = dtb.NewRow();
                        dr["ljg"] = txtWLBM.Text.ToString().Trim() + code;//物料编码+4位流水号
                        dr["DYFS"] = txtDyfs.Text.ToString().Trim();
                        //dr["ZSMF"] = txtZsmf.Text.ToString().Trim();
                        dtb.Rows.Add(dr);
                    }
                    lblTitle.Text = dtb.ToString();
                }

                
                  

                string MACmodel = @"LJG_QRcode.lab";//模板

                Application.DoEvents();
                Printer Macpts = new Printer();

                Macpts.PrintMAC(dtb, "", "", "", Convert.ToInt32(txtDyfs.Text.ToString().Trim()), MACmodel, out err);

                lblWarm.Text = err;


            }
            else
            {
                lblWarm.Text = " 打印失败！";
                lblWarm.ForeColor = Color.Red;
            }
            #endregion
        }
         
public bool PrintMAC(DataTable dtb, string barcode, string Prefix, string SerNum, int ptnum, string model, out string error)
    {
        Kill("lppa");
         model = AppDomain.CurrentDomain.BaseDirectory + model;//取当前应用程序域运行的目录
        LabelManager2.ApplicationClass PrintApp = new LabelManager2.ApplicationClass();

        try
        {
            LabelManager2.Document PrintDoc = PrintApp.ActiveDocument;
            PrintDoc = PrintApp.Documents.Open(model, false);
            if (PrintDoc == null)
            {
                error = "模版未找到";
                return false;
            }

            if (!string.IsNullOrEmpty(barcode))
            {
                PrintDoc.Variables.Counters.Item(barcode).Prefix = Prefix;
                PrintDoc.Variables.Counters.Item(barcode).Value = SerNum;
            }

            for (int j = 0; j < dtb.Rows.Count; j++) //行
            {
                for (int i = 0; i < dtb.Columns.Count; i++) //列
                {
                    try
                    {
                        string col = dtb.Columns[i].ColumnName.ToString();
                        string txt = dtb.Rows[j][col].ToString();
                        PrintDoc.Variables.Item("ljg").Value = txt;//给模板的变量传值    
                    }
                    catch (Exception ex)
                    {
                        error = ex.Message;
                        return false;
                    }
                }
                //打印预览
                 PrintPreviewDialog dialog = new PrintPreviewDialog();
                dialog.Document = this.PrintDoc;
                dialog.ShowDialog();
                PrintDoc.PrintDocument(1);

            }
            error = "打印成功";
            return true;

        }
        catch (Exception ex)
        {
            error = ex.Message;
            return false;
        }
        finally
        {
            PrintApp.Documents.CloseAll(false);
            PrintApp.Quit();
        }

Answer 1

把代码贴出来先。

Answer 2

可以先打印预览是否正常