我正在使用C＃创建一个Native IOS应用程序。我有一个注册表格，我发送带有图像的表格数据。但我无法发送图像，因为我的UIImage控件不包含其路径或名称。我将表单发送到多个部分的web api。文本字段数据正在上传，但图片没有上传。
答案 0 :(得分：2)
以下是如何从相机/图库中选择图像到UIImageView，然后上传;
使用UIImagePickerController从图库/相机中选择图像
UIImagePickerController galleryImagePicker;
UIImagePickerController cameraImagePicker;
使用以下功能单击按钮或在ImageView上使用弹出按钮在相机/图库之间进行选择：
void ShowSelectPicPopup ()
{
var actionSheetAlert = UIAlertController.Create ("Select picture",
"Complete action using", UIAlertControllerStyle.ActionSheet);
actionSheetAlert.AddAction (UIAlertAction.Create ("Camera",
UIAlertActionStyle.Default, (action) => HandleCameraButtonClick ()));
actionSheetAlert.AddAction (UIAlertAction.Create ("Gallery",
UIAlertActionStyle.Default, (action) => HandleGalleryButtonClick ()));
actionSheetAlert.AddAction (UIAlertAction.Create ("Cancel", UIAlertActionStyle.Cancel,
(action) => Console.WriteLine ("Cancel button pressed.")));
// Required for iPad - You must specify a source for the Action Sheet since it is
// displayed as a popover
var presentationPopover = actionSheetAlert.PopoverPresentationController;
if (presentationPopover != null) {
presentationPopover.SourceView = View;
presentationPopover.PermittedArrowDirections = UIPopoverArrowDirection.Up;
}
PresentViewController (actionSheetAlert, true, null);
}
现在的行动：
void HandleGalleryButtonClick ()
{
if (galleryImagePicker == null) {
galleryImagePicker = new UIImagePickerController ();
galleryImagePicker.SourceType = UIImagePickerControllerSourceType.PhotoLibrary;
galleryImagePicker.MediaTypes = UIImagePickerController.AvailableMediaTypes (UIImagePickerControllerSourceType.PhotoLibrary);
galleryImagePicker.FinishedPickingMedia += Handle_FinishedPickingMedia;
galleryImagePicker.Canceled += Handle_Canceled;
}
PresentViewController (galleryImagePicker, true, () => { });
}
void HandleCameraButtonClick ()
{
if (cameraImagePicker == null) {
cameraImagePicker = new UIImagePickerController ();
cameraImagePicker.PrefersStatusBarHidden ();
cameraImagePicker.SourceType = UIImagePickerControllerSourceType.Camera;
cameraImagePicker.FinishedPickingMedia += Handle_FinishedPickingCameraMedia;
cameraImagePicker.Canceled += Handle_CameraCanceled;
}
PresentViewController (cameraImagePicker, true, () => { });
}
void Handle_Canceled (object sender, EventArgs e)
{
galleryImagePicker.DismissViewController (true, () => { });
}
protected void Handle_FinishedPickingMedia (object sender, UIImagePickerMediaPickedEventArgs e)
{
// determine what was selected, video or image
bool isImage = false;
switch (e.Info [UIImagePickerController.MediaType].ToString ()) {
case "public.image":
Console.WriteLine ("Image selected");
isImage = true;
break;
case "public.video":
Console.WriteLine ("Video selected");
break;
}
// get common info (shared between images and video)
var referenceURL = e.Info [new NSString ("UIImagePickerControllerReferenceUrl")] as NSUrl;
if (referenceURL != null)
Console.WriteLine ("Url:" + referenceURL);
// if it was an image, get the other image info
if (isImage) {
// get the original image
var originalImage = e.Info [UIImagePickerController.OriginalImage] as UIImage;
if (originalImage != null) {
// do something with the image
Console.WriteLine ("got the original image");
Picture.Image = originalImage; // Picture is the ImageView
picAssigned = true;
}
} else { // if it's a video
// get video url
var mediaURL = e.Info [UIImagePickerController.MediaURL] as NSUrl;
if (mediaURL != null) {
Console.WriteLine (mediaURL);
}
}
// dismiss the picker
galleryImagePicker.DismissViewController (true, () => { });
}
protected void Handle_FinishedPickingCameraMedia (object sender, UIImagePickerMediaPickedEventArgs e)
{
// determine what was selected, video or image
bool isImage = false;
switch (e.Info [UIImagePickerController.MediaType].ToString ()) {
case "public.image":
Console.WriteLine ("Image selected");
isImage = true;
break;
case "public.video":
Console.WriteLine ("Video selected");
break;
}
// get common info (shared between images and video)
var referenceURL = e.Info [new NSString ("UIImagePickerControllerReferenceUrl")] as NSUrl;
if (referenceURL != null)
Console.WriteLine ("Url:" + referenceURL);
// if it was an image, get the other image info
if (isImage) {
// get the original image
var originalImage = UIHelper.RotateCameraImageToProperOrientation (e.Info [UIImagePickerController.OriginalImage] as UIImage, 320);
if (originalImage != null) {
// do something with the image
Console.WriteLine ("got the original image");
Picture.Image = originalImage; // display
picAssigned = true;
}
} else { // if it's a video
// get video url
var mediaURL = e.Info [UIImagePickerController.MediaURL] as NSUrl;
if (mediaURL != null) {
Console.WriteLine (mediaURL);
}
}
// dismiss the picker
cameraImagePicker.DismissViewController (true, () => { });
}
void Handle_CameraCanceled (object sender, EventArgs e)
{
cameraImagePicker.DismissViewController (true, () => { });
}
您可能需要在Info.plist中添加以下两个权限才能访问相机/图库
Privacy - Camera Usage Description
Privacy - Photo Library Usage Description
他们都是String，而Value可以是＆＃34; YourAppName需要访问才能使用你的相机＆＃34;
最后将图片上传为多部分：
首先将图像转换为字节数组
public static byte[] ConvertImageToByteArray(UIImage Picture) {
byte [] image = null;
try {
using (NSData imageData = Picture.Image.AsJPEG (0.5f)) { // Here you can set compression %, 0 = no compression, 1 = max compression, or the other way around, I'm not sure
image = new byte [imageData.Length];
Marshal.Copy (imageData.Bytes, image, 0, Convert.ToInt32 (imageData.Length));
} catch (Exception e) {
Console.WriteLine ("Error @ Picture Byte Conversion: " + e.Message);
}
return image;
}
最后发布图片，我使用了modernhttpclient
public async Task PostPicture (byte [] image)
{
try {
string url = .....;
var requestContent = new MultipartFormDataContent ();
ByteArrayContent content = content = new ByteArrayContent (image);
content.Headers.ContentType = MediaTypeHeaderValue.Parse ("image/jpeg");
requestContent.Add (content, "file", "post" + DateTime.Now + ".jpg"); // change file name as per your requirements
string result = await HttpCall.PostMultiPartContent (url, requestContent, null);
} catch (Exception ex) {
System.Diagnostics.Debug.WriteLine (ex.Message);
}
}
public class HttpCall
{
public static async Task<string> PostMultiPartContent (string url, MultipartFormDataContent content, Action<int> progressAction) // Here you can pass an handler to keep track of the upload % in your UI, I'm passing null above. (Not keeping track)
{
try {
var request = new HttpRequestMessage (HttpMethod.Post, url);
var progressContent = new ProgressableStreamContent (content, 4096, (sent, total) => {
var percentCompletion = (int)(((double)sent / total) * 100);
System.Diagnostics.Debug.WriteLine ("Completion: " + percentCompletion);
if (progressAction != null)
progressAction (percentCompletion);
});
request.Content = progressContent;
var client = new HttpClient();
var response = await client.SendAsync (request);
string result = await response.Content.ReadAsStringAsync ();
System.Diagnostics.Debug.WriteLine ("PostAsync: " + result);
return result;
} catch (Exception e) {
System.Diagnostics.Debug.WriteLine (e.Message);
return null;
}
}
}