如何从Windows.Storage.StorageFile WinJS加载blob

Question

我正在使用WinJS开发一个Metro应用程序，它打开我的相机，拍摄并创建一张图片，将结果存储在Windows.Storage.StorageFile对象（ capturedItem ）上我想从它们创建一个blob对象

这是我的方法：

 function imageCapture() {

        var captureUI = new _capture.CameraCaptureUI();

        captureUI.photoSettings.format = _capture.CameraCaptureUIPhotoFormat.jpeg;
        captureUI.captureFileAsync(_capture.CameraCaptureUIMode.photo)
            .then(function (capturedItem) {
                if (capturedItem) {

                    var photoBlobUrl = URL.createObjectURL(
                        capturedItem,
                        { oneTimeOnly: true });

                    imageElement = document.createElement("img");
                    imageElement.id = "img1";
                    imageElement.setAttribute("src", photoBlobUrl);

                    _divPicture.appendChild(imageElement);

                    // prints in textfield blob value
                    document.getElementById("field1").value = capturedItem.path;
                }
            }
        );
    }

Answer 1

你其实非常接近。您应该首先从capturedItem创建一个文件。像这样：

var file = MSApp.createFileFromStorageFile(capturedItem);
// than use the file variable in the createObjectURL function
var url = URL.createObjectURL(file, { oneTimeOnly: true });
var imageElement = document.createElement("img");
imageElement.id = "img1";
imageElement.setAttribute("src", url);
_divPicture.appendChild(imageElement);