I have an ASP.NET web app. What I am attempting should be simple: after an image is displayed, I have a Rotate button which should allow the user to rotate the image 90 degrees. Here is the button click code...
Dim i As Image
i = Image.FromFile("C:\Inetpub\wwwroot\myWebApp\MyImage.jpg")
'rotate the picture by 90 degrees
i.RotateFlip(RotateFlipType.Rotate90FlipNone)
're-save the picture as a Jpeg
i.Save("C:\Inetpub\wwwroot\myWebApp\MyImage.jpg",System.Drawing.Imaging.ImageFormat.Jpeg)
'tidy up after we've finished
i.Dispose()
The image and button used here are non-remarkable. When I created a sample app with just 1 page this works perfectly. However, when I put in into my main app, even if its in a new page, all by itself with nothing else, not even a masterpage, it does, in fact rotate the image and write it back to the file system, but it doesn't show the rotated file. It shows the image as it was. UNTIL I hit F5, then, no matter how many times I hit the button, it works perfectly. I have tried eveything i can think of to clear the cashe to no avail.
Are you re-requesting the image using an update panel or some other mechanism? You will be able to force a refresh by putting something like a timestamp or similar GET parameter on the IMG src, or in the ASP:Image source.
Instead of saving the image back to the web root you can keep the original image as is and just stream the rotated image to the client.
<img src="RotateImage.aspx?Image=MyImage.jpg&Rotate=90" />
and then in your RoateImage.aspx do the same load/rotate work and:
i.Save(Response.OutputStream, ImageFormat.Jpeg)
Response.ContentType = "image/jpeg"
The image is served from the cache, that is why it is not shown updated. To show the newer version of the same image. You may attach a query string to the path of the image. For example,
<img src='/images/image.jpg?<%= DateTime.Now.Ticks %>' />
Related
On Page_Load, I want the page to display an image the same way it displays when you "Open image in a new tab". In other words, I want the page to display as content type Image/jpeg instead of rendering the image in img HTML tag.
I successfully displayed an image this way using the below code on Page_Load:
Page.Response.ContentType="image/jpeg"
Page.Response.WriteFile("Path_to_the_Image")
However, my case requires displaying the image after being resized. I created a function that resizes the image and returns the resized image as Drawing.Bitmap
ResizeImage(bmSource As Drawing.Bitmap, TargetWidth As Int32, TargetHeight As Int32)
How can I use the returned value of that function and display it the same way I displayed the first image?
Page.Response.WriteFile() requires a String as an input. Is there a way where I can display the image of type Image or System.Bitmap directly into the page without having to save it in a temp folder and then use its path (As a String) and pass it to Page.Response.WriteFile?
Page.Response.ContentType="image/jpeg"
Using resizedImage As Bitmap = ResizeImage(source, 100, 100)
source.Dispose()
resizedImage.Save(Page.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg)
End Using
Page.Response.Flush()
That should work, maybe there's some error in my syntax. I do not often code in vb.net so.
Edited the code because of #Joel Coehoorn note
So I would like to be able to have a print button for entries in our database so users can print an entry via a print friendly "form".
My thought was to create a separate page, add labels and have those labels pull the relevant information.
I know I can add the open widget information via this code:
app.datasources.ModelName.selectKey(widget.datasource.item._key);
app.showPage(app.pages.TestPrint);
But I'm running into a few problems:
I can't get the page to open in a new window. Is this possible?
window.open(app.pages.TestPrint);
Just gives me a blank page. Does the browser lose the widget source once the new window opens?
I can't get the print option (either onClick or onDataLoad) to print JUST the image (or widget). I run
window.print();
And it includes headers + scroll bars. Do I need to be running a client side script instead?
Any help would be appreciated. Thank you!
To get exactly what you'd want you'd have to do a lot of work.
Here is my suggested, simpler answer:
Don't open up a new tab. If you use showPage like you mention, and provide a "back" button on the page to go back to where you were, you'll get pretty much everything you need. If you don't want the back to show up when you print, then you can setVisibility(false) on the button before you print, then print, then setVisibility(true).
I'll give a quick summary of how you could do this with a new tab, but it's pretty involved so I can't go into details without trying it myself. The basic idea, is you want to open the page with a full URL, just like a user was navigating to it.
You can use #TestPrint to indicate which page you want to load. You also need the URL of your application, which as far as I can remember is only available in a server-side script using the Apps Script method: ScriptApp.getService().getUrl(). On top of this, you'll probably need to pass in the key so that your page knows what data to load.
So given this, you need to assemble a url by calling a server script, then appending the key property to it. In the end you want a url something like:
https://www.script.google.com/yourappaddress#TestPage?key=keyOfYourModel.
Then on TestPage you need to read the key, and load data for that key. (You can read the key using google.script.url).
Alternatively, I think there are some tricks you can play by opening a blank window and then writing directly to its DOM, but I've never tried that, and since Apps Script runs inside an iframe I'm not sure if it's possible. If I get a chance I'll play with it and update this answer, but for your own reference you could look here: create html page and print to new tab in javascript
I'm imagining something like that, except that your page an write it's html content. Something like:
var winPrint = window.open('', '_blank', 'left=0,top=0,width=800,height=600,toolbar=0,scrollbars=0,status=0');
winPrint.document.write(app.pages.TestPage.getElement().innerHTML);
winPrint.document.close();
winPrint.focus();
winPrint.print();
winPrint.close();
Hope one of those three options helps :)
So here is what I ended up doing. It isn't elegant, but it works.
I added a Print Button to a Page Fragment that pops up when a user edits a database entry.
Database Edit Button code:
app.datasources.ModelName.selectKey(widget.datasource.item._key);
app.showDialog(app.pageFragments.FragmentName);
That Print Button goes to a different (full) Page and closes the Fragment.
Print Button Code:
app.datasources.ModelName.selectKey(widget.datasource.item._key);
app.showPage(app.pages.ModelName_Print);
app.closeDialog();
I made sure to make the new Print Page was small enough so that Chrome fits it properly into a 8.5 x 11" page (728x975).
I then created a Panel that fills the page and populated the page with Labels
#datasource.item.FieldName
I then put the following into the onDataLoad for the Panel
window.print();
So now when the user presses the Print Button in the Fragment they are taken to this new page and after the data loads they automatically get a print dialog.
The only downside is that after printing the user has to use a back button I added to return to the database page.
1.
As far as I know, you cannot combine window.open with app.pages.*, because
window.open would require url parameter at least, while app.pages.* is essentially an internal routing mechanism provided by App Maker, and it returns page object back, suitable for for switching between pages, or opening dialogs.
2.
You would probably need to style your page first, so like it includes things you would like to have printed out. To do so please use #media print
ex: We have a button on the page and would like to hide it from print page
#media print {
.app-NewPage-Button1 {
display : none;
}
}
Hope it helps.
1. Here is how it is done, in a pop up window, without messing up the current page (client script):
function print(widget, title){
var content=widget.getElement().innerHTML;
var win = window.open('', 'printWindow', 'height=600,width=800');
win.document.write('<head><title>'+title+'/title></head>');
win.document.write('<body>'+content+'</body>');
win.document.close();
win.focus();
win.print();
win.close();
}
and the onclick handler for the button is:
print(widget.root.descendants.PageFragment1, 'test');
In this example, PageFragment1 is a page fragment on the current page, hidden by adding a style with namehidden with definition .hidden{display:none;} (this is different than visible which in App Maker seems to remove the item from the DOM). Works perfectly...
2. You cannot open pages from the app in another tab. In principle something like this would do it:
var w=window.parent.parent;
w.open(w.location.protocol+'//'+w.location.host+w.location.pathname+'#PrintPage', '_blank');
But since the app is running in frame nested two deep from the launching page, and with a different origin, you will not be able to access the url that you need (the above code results in a cross origin frame access error). So you would have to hard code the URL, which changes at deployment, so it gets ugly very fast. Not that you want to anyway, the load time of an app should discourage you from wanting to do that anyway.
I'm working in ASP.NET (2.0) and we have a page where a user is able to select and download a series of files as a zip. I got this to work without undo difficulty by using the DotNetZip library (which is probably not relevant to the problem, but included for completeness.)
After the user checks which files they want to download, the page does a postback, and in the button click event handler, I use the following code:
Response.Clear();
Response.BufferOutput = false; // false = stream immediately
Response.ContentType = "application/zip";
Response.AddHeader("content-disposition", "filename=FileRequest.zip");
using (ZipFile zip = new ZipFile())
{
zip.AddFile(MapPath("/datafiles/fileToZip.pdf"), "");
zip.Save(Response.OutputStream);
}
Response.Close();
And this all seems to work great. The user clicks the button, a download window pops up, the user downloads the zip. All is good...
...until they decide they want to do something else on the page. The buttons in the form are no longer responsive. For instance, if I click the download button again, it does nothing. If I reload the page, I can repeat this behavior...it works once, then does nothing.
I'm not understanding why the browser doesn't send the new request. It's not "spinning" or otherwise acting busy. I thought that this might be a browser issue, but I've repeated it in both IE and Firefox, so it seems likely that it's something I'm not understanding. Strangely, it's only form submission elements that seem to be non-responsive. Javascript still works, and so do regular links.
So why is this happening, and how do I get around it?
The problem is likely down to you returning;
Response.ContentType = "application/zip";
Once this has been sent (along with the actual content), the browser would assume it has nothing left to do (I believe).
You probably should create a new window specifically for downloading the files by saving the file selection in a session parameter (or equivalent) and opening a popup window that has your download code in.
This will leave the parent page in a suitable state.
Content-disposition header seems to be a discouraged solution. But the same effect of ASP.NET forms not being responsive occurs if you use standard Redirect to a zip file.
I solved very similar problem (returning *.csv files by the server for download) using Tančev Saša's code in "Response.Redirect to new window" Q&A and it works great. Perhaps it might produce some popup warnings in some browsers, but I think this is how it's often done in download sites.
Hi im using the RadToolTip.
<asp:Image ID="imgMain" runat="server"/>
<telerik:RadToolTip ID="RadToolTip2" runat="server" TargetControlID="imgMain" Width="400px" RelativeTo="Element" EnableShadow="true" Position="BottomCenter" Animation="Slide" AnimationDuration="300" ShowDelay="200" Skin="Vista" HideEvent="LeaveToolTip">
</telerik:RadToolTip>
Im also adding a Image inside the RadToolTip at runtime, the ImageUrl of this Image is set via my own custom Image Handler which is used within the site and works fine.
When the user hovers over 'imgMain' the RadToolTip should show the same image but at a different size, but all im getting is the RadToolTip showing the title.
If i hard code the Image Urls into the Image inside the RadToolTip is shows fine so i know its not a problem with my ImageHandler.
Is there any known issues with dynamically showing images from a Image Handler inside a RadToolTip?
My Server side code is below
imgMain.ImageUrl = String.Format("~/dbimagehandler.ashx?record=product&empty=showt&imageno=1&recno=-1&wid={0}&hgt={1}&productid={2}", "188", "196", this.ProductId)
imgMain.AlternateText = ds.Ds.Tables["Table"].Rows[0]["Title"].ToString();
imgMain.ToolTip = ds.Ds.Tables["Table"].Rows[0]["Title"].ToString();
RadToolTip2.TargetControlID = imgMain.ID;
Image imgsmall = new Image();
imgsmall.ImageUrl = String.Format("~/dbimagehandler.ashx?record=product&empty=showt&imageno=1amprecno=-1&wid={0}&hgt={1}&productid={2}", "376","392", this.ProductId);
RadToolTip2.Controls.Add(imgsmall);
Any help on this would be much apreciated.
In what event are you adding this image to the tooltip? If it is in an AJAX request make sure that the tooltip is updated as well. You can also check the net tab to see if the request for your image actually returns an image and not 404, which would be a very good reason for a missing image.
You can also try putting an image in the markup and setting only its url from the server, or even via JavaScript on the client (for example in the OnClientShow event, by storing the URL in a hidden field).
You can also take a look at the Load-on-demand the RadToolTipManager offers, for example form the telerik demo site, for example here, as it would fit very nicely with the way you dynamically create an image.
Not sure if you already are doing so but make sure that you have following kind of code in your code behind ( I use C# )
private void LoadTree()
{
RadToolTipManager1.ShowDelay = 100;
RadToolTipManager1.HideDelay = 100;
RadToolTipManager1.AutoCloseDelay = 8000;
RadToolTipManager1.TargetControls.Add("<ID Of the Control where you wish to diplay the rad tool tip>");
}
This might help. I noticed some funky behavior with the RadToolTips after some recent updates...so I went to a RadToolTipManager with an Ajax update. Just put your handler code in the Ajax event.
http://trappedinhoth.blogspot.com/2014/05/fixing-teleriks-radtooltip-after-latest.html
I hope that helps.
I am using asp.net 3.5 and C#.
I have a image which I want user can download.
Like, there would be a download button or link. When user click on this link he will be prompted with a pop up to save that image to his desktop.
I have tried with
<a href ="path" > </a>
but it is opening the image in other page, I want user to be prompted to either save or view the image,
please help
Thanks in advance
You need to write an IHttpHandler that serves the image along with a Content-Disposition header.
For example:
Response.AppendHeader("Content-Disposition", "attachment; filename=\"MyImage.png\"");
Response.TransmitFile(path);
You would probably pass the image name on the query-string.
If so, make sure it doesn't contain / or \, or attackers will be able to read arbitrary files.
You need to have another page or, better yet, an HttpHandler, that takes the image path as part of the query string or as a post parameter that will send the response with Content-Disposition set to attachment. Setting the content disposition this way will cause the browser to display the file download dialog. A slightly easier way, though it depends on the user doing something extra is simply to have the link open the image in a new page and let the user right-click on it and do a "Save As".
Download
or
<a href="/path/to/image" target="_blank">
Load Image in New Window then Use Save As</a>