使用字节数组添加多个 ITextSharp 二进制图像会导致 IndexOutOfRangeException

Question

我正在使用 ITextSharp 和 html2canvas 来添加二进制图像 和 PDF 生成。

下面是我的Codebehind 代码的 sn-p。

var overallResultsBase64string = hdnOverallResults.Value.Replace("data:image/png;base64,", "");
var appServerCapacityBase64string = hdnAppServerCapacity.Value.Replace("data:image/png;base64,", "");
var appPerformanceBase64string = hdnAppPerformance.Value.Replace("data:image/png;base64,", "");
var dbServerCapacityBase64string = hdnDBServerCapacity.Value.Replace("data:image/png;base64,", "");
var dbPerformanceBase64string = hdnDBPerformance.Value.Replace("data:image/png;base64,", "");

iTextSharp.text.Image overallResultsImg, appServerCapacityImg, appPerformanceImg
  , dbServerCapacityImg, dbPerformanceImg;

byte[] overallResultsBytes = Convert.FromBase64String(overallResultsBase64string);
overallResultsImg = iTextSharp.text.Image.GetInstance(overallResultsBytes);
byte[] appServerCapacityBytes = Convert.FromBase64String(appServerCapacityBase64string);
appServerCapacityImg = iTextSharp.text.Image.GetInstance(appServerCapacityBytes);
byte[] appPerformanceBytes = Convert.FromBase64String(appPerformanceBase64string);
appPerformanceImg = iTextSharp.text.Image.GetInstance(appPerformanceBytes);
byte[] dbServerCapacityBytes = Convert.FromBase64String(dbServerCapacityBase64string);
dbServerCapacityImg = iTextSharp.text.Image.GetInstance(dbServerCapacityBytes);
byte[] dbPerformanceBytes = Convert.FromBase64String(dbPerformanceBase64string);
dbPerformanceImg = iTextSharp.text.Image.GetInstance(dbPerformanceBytes);

document.Add(overallResultsImg);
document.Add(new Paragraph("OVERALL APPLICATION PERFORMANCE"));
document.Add(appPerformanceImg);
document.Add(dbPerformanceImg);
document.Add(new Paragraph("OVERALL SERVER CAPACITY"));
document.Add(appServerCapacityImg);
document.Add(dbServerCapacityImg);

var appServerCapacityBase64string 是 NULL，它会在

上引发 IndexOutOfBounds 异常

byte[] appServerCapacityBytes = Convert.FromBase64String(appServerCapacityBase64string);
appServerCapacityImg = iTextSharp.text.Image.GetInstance(appServerCapacityBytes);

我下面的 Javascript html2canvas 代码有问题吗？请检查。

<script>
   html2canvas($("#overallResultsDiv"), {
        onrendered: function (canvas) {
            // canvas is the final rendered <canvas> element
            var myImage = canvas.toDataURL("image/png");
            document.getElementById("hdnOverallResults").value = myImage;
        }
    });

    html2canvas($("#appServerCapacityDiv"), {
        onrendered: function (canvas) {
            // canvas is the final rendered <canvas> element
            var myImage = canvas.toDataURL("image/png");
           $("#hdnAppServerCapacity").value = myImage;
        }
    });

    html2canvas($("#appPerformanceDiv"), {
        onrendered: function (canvas) {
            // canvas is the final rendered <canvas> element
            var myImage = canvas.toDataURL("image/png");
            document.getElementById("hdnAppPerformance").value = myImage;
        }
    });

    html2canvas($("#dbServerCapacityDiv"), {
        onrendered: function (canvas) {
            // canvas is the final rendered <canvas> element
            var myImage = canvas.toDataURL("image/png");
            document.getElementById("hdnDBServerCapacity").value = myImage;
        }
    });

    html2canvas($("#dbPerformanceDiv"), {
        onrendered: function (canvas) {
            // canvas is the final rendered <canvas> element
            var myImage = canvas.toDataURL("image/png");
            document.getElementById("hdnDBPerformance").value = myImage;
        }
    });
</script>

仅 第一个 html2canvas 成功将 base64 string 作为值传递给相应的 HiddenField 并且成功 strong> 在CodeBehind 中访问。我的脚本有什么问题导致5 HiddenFields 返回NULL？

Answer 1

您是否尝试过在您的函数中将var myImage = canvas.toDataURL("image/png"); 更改为不同的名称？