ReferenceError: label is not defined in Dymo framework

Question

我正在玩 Dymo's JS framework. The original example 没有问题，但它正在加载 XML 即使我不想点击。我重写为仅在调用时执行 Dymo 代码：

<script type="text/javascript">
       function printnow() {              
               $.get("./cont.label", function(labelXml) {
               label = dymo.label.framework.openLabelXml(labelXml);
               }, "text");
               // open label
               // set label text
               label.setObjectText("MENO", "test");
               label.setObjectText("MUNKA", "test");
               label.setObjectText("DESCRIPTION", test);
               // select printer to print on
               // for simplicity sake just use the first LabelWriter printer
               var printers = dymo.label.framework.getPrinters();
               if (printers.length == 0) throw "No DYMO printers are installed. Install DYMO printers.";
               var printerName = "";
               for (var i = 0; i < printers.length; ++i) {
                   var printer = printers[i];
                   if (printer.printerType == "LabelWriterPrinter") {
                       printerName = printer.name;
                       break;
                   }
               }
               if (printerName == "") throw "No LabelWriter printers found. Install LabelWriter printer";
               // finally print the label
               label.print(printerName);

       };
</script> 

不幸的是，在我调用 printnow() 之后；我得到 ReferenceError: label is not defined 问题出在哪里？

Answer 1

首先你必须阅读这个one。

简而言之，您正在处理异步代码。因此，此 label.setObjectText("MENO", "test"); 和其余代码在 label = dymo.label.framework.openLabelXml(labelXml); 行之前执行。

最后，你必须做这样的事情：

<script type="text/javascript">
       function printnow() {              
               $.get("./cont.label", function(labelXml) {
               var label = dymo.label.framework.openLabelXml(labelXml);
               // open label
               // set label text
               label.setObjectText("MENO", "test");
               label.setObjectText("MUNKA", "test");
               label.setObjectText("DESCRIPTION", test);
               // select printer to print on
               // for simplicity sake just use the first LabelWriter printer
               var printers = dymo.label.framework.getPrinters();
               if (printers.length == 0) throw "No DYMO printers are installed. Install DYMO printers.";
               var printerName = "";
               for (var i = 0; i < printers.length; ++i) {
                   var printer = printers[i];
                   if (printer.printerType == "LabelWriterPrinter") {
                       printerName = printer.name;
                       break;
                   }
               }
               if (printerName == "") throw "No LabelWriter printers found. Install LabelWriter printer";
               // finally print the label
               label.print(printerName);

               }, "text");

       };
</script>