I have a Data table which a has a column for images.
I am using the following code to read the image
byte[] Logo = (byte[])dt_Info.Rows[0]["Logo"];
But it got this error :
Unable to cast object of type 'System.String' to type 'System.Byte[]'.
In addition I Save the image binary code in ''bytes".
When I Write this Code , it works correctly.
byte[] Logo = bytes;
What Should I do to handle the error and read image from Data-table?
byte[] array = Encoding.ASCII.GetBytes(dt_Info.Rows[0]["Logo"].ToString());
you can get byte array like this
string s = (string)dt_Info.Rows[0]["Logo"];
byte[] data = System.Text.Encoding.ASCII.GetBytes(s);
Related
I have an excel file that contains all the filenames of the Images. The path of these images are stored in an Observable Collection via <File> class which came from the folder that contains all of the images. My goal is to create a hyperlink of these filenames by matching it through the pool of image file collection.
I would like to ask if how can I iterate faster through a large collection of file classes in order to get their paths easily.
For example:
Image name from Excel :
ABC_0001
The Full path from the collection must be:
C:\Users\admin\Desktop\Images\ABC_0001.jpg
In order to get their full path, I perform the iteration through Stream.
My procedures:
Extract data using Apache POI.
Stream through the Image Collection by converting each data into
their base filenames vs extracted data.
Get the result and store the fullpath on the object via
getAbsolutePath().
Code:
//storage during iteration
ObservableList<DetailedData> dataCollection = FXCollections.observableArrayList()
//Image collection containing over 13k Images listed via commons-io
ObservableList<File> IMAGE_COLLECTION = FXCollections.observableArrayList(FileUtils.listFiles(browsedFOLDER, new String[]{"JPG", "JPEG", "TIF", "TIFF", "jpg", "jpeg", "tif", "tiff"}, true));
//Sheet data
Sheet sheet1 = wb.getsheetAt(0);
for (Row row: sheet1)
{
DetailedData data = new DetailedData();
//extracted data from excel
String FILENAME = row.getCell(0,Row.MissingCellPolicy.CREATE_NULL_AS_BLANK).getStringCellValue();
//to be filled up based on stream result.
String IMAGE_SOURCE = null;
//stream code with the help of commons-io
File IMAGE = IMAGE_COLLECTION.stream().filter(e -> FilenameUtils.getBaseName(e.getName()).toLowerCase().equals(FILENAME.toLowerCase())).findFirst().orElse(null);
if (IMAGE != null)
IMAGE_SOURCE = IMAGE.getAbsolutePath();
data.setFileName(FILENAME);
data.setFullPath(IMAGE_SOURCE);
dataCollection.add(data);
}
Result:
Excel rows = 9,400
Image Files = 13,000
Iteration Time = 120,000ms
Are the results should appear normal or it can become faster?
I tried using parallelStream() and the results went faster but it consumes higher CPU usage.
This code should speed your code up a lot, but there are a few questions about your code.
ObservableList<DetailedData> dataCollection = FXCollections.observableArrayList() Why are you using ObservableList? Why is this a list of DetailedData and not File. Given that detailed data has setFileName and setFullPath. File already has these.
ObservableList<File> IMAGE_COLLECTION = FXCollections.observableArrayList(FileUtils.listFiles(browsedFOLDER, new String[]{"JPG", "JPEG", "TIF", "TIFF", "jpg", "jpeg", "tif", "tiff"}, true)); Why ObservableList?
These two are small things, but I am curious.
So what I think you should do is use a Map. Your code should look something like the code below.
//storage during iteration
List<DetailedData> dataCollection = new ArrayList();
//Image collection containing over 13k Images listed via commons-io
List<File> IMAGE_COLLECTION = new ArrayList(FileUtils.listFiles(new File("C:\\Users\\blj0011\\Pictures"), new String[]{"JPG", "JPEG", "TIF", "TIFF", "jpg", "jpeg", "tif", "tiff"}, true));
//Use this to map file name to file
Map<String, File> map = new HashMap();
//Use this to add data to the map
IMAGE_COLLECTION.forEach((file) -> {map.put(file.getName().substring(0, file.getName().lastIndexOf(".")).toLowerCase(), file);});
for (Row row: sheet1)
{
//extracted data from excel
String FILENAME = row.getCell(0,Row.MissingCellPolicy.CREATE_NULL_AS_BLANK).getStringCellValue();
//If the map contains the file name, create `DetailedData` object. Then set data. Then add object to datacollection list.
if (map.containsKey(FILENAME.toLowerCase()))
{
DetailedData data = new DetailedData();
data.setFileName(FILENAME);
data.setFullPath(map.get(FILENAME.toLowerCase()).getAbsolutePath());
dataCollection.add(data);
}
}
Comments in the code
I still believe this could be cleaned up a little more if you used List<File> dataCollection = new ArrayList()
If you really want to speed up your search, you should try not to do things repeatedly which could just be done once. For example you could use two loops. The first to prepare your search and the second to actually do the search. Inside your filter you call FilenameUtils.getBaseName and two time a conversion to lower case. It would be better to do these things only once in the first loop and store the resulting Strings in a list. In the second loop you then do the search on this list.
I am also wondering why you use ObservableLists here. A simple List would do as well.
I've tested another approach in this slow iteration.
It seems that the cause is declaring the Stream repeatedly inside the foreach.
I tried using Baeldung's solution <Supplier> and declared it outside the loop together with parallelStream()
Sample Code:
Supplier<Stream<File>> streamSupplier = () -> imageCollection.parallelStream();
for (Row row : sheet)
{
File IMAGE = streamSupplier.get().filter(e -> FilenameUtils.getBaseName(e.getName()).toLowerCase().equals(FILENAME.toLowerCase())).findFirst().orElse(null);
if (IMAGE != null)
IMAGE_SOURCE = IMAGE.getAbsolutePath();
}
Result went 45000ms
Please correct me if my approach was not right.
I have Xamarin.Forms project. I have textbox in that and have a button which get text from textbox and pass it to API to store. Now the point is when user select any emojis from keyboard, I want to get unicode character of the emojis. Currently I am getting emojis it self when I check Text property of it.
I want to get Unicode rather emoji as given in NewTextValue from Text property.
This post is same but I don't understand how the guy has managed. POST
Please suggest.
After some google, I have tried with following.
string res = BitConverter.ToString(Encoding.BigEndianUnicode.GetBytes(str)).Replace("-", "");
This is result res = D83DDE00
I don't know above code is unicode or not.
How can I convert back to original emoji or is there any other way to convert in unicode?
We need to manually convert it back. Insert "-" every two characters:
var convertStr = string.Join("-", Regex.Matches(res, #"..").Cast<Match>().ToList());
String[] tempArr = convertStr.Split('-');
byte[] decBytes = new byte[tempArr.Length];
for (int i = 0; i < tempArr.Length; i++)
{
decBytes[i] = Convert.ToByte(tempArr[i], 16);
}
String str = Encoding.BigEndianUnicode.GetString(decBytes);
Moreover in my test, Encoding.UTF32.GetBytes() may be closer to emoji code. You can test it with \U0001F600, this is a smile image. After converting with utf32, the bytes just change its order.
How can I convert an image to array of bytes using ImageSharp library?
Can ImageSharp library also suggest/provide RotateMode and FlipMode based on EXIF Orientation?
If you are looking to convert the raw pixels into a byte[] you do the following.
var bytes = image.SavePixelData()
If you are looking to convert the encoded stream as a byte[] (which I suspect is what you are looking for). You do this.
using (var ms = new MemoryStream())
{
image.Save(ms, imageFormat);
return ms.ToArray();
}
For those who look after 2020:
SixLabors seems to like change in naming and adding abstraction layers, so...
Now to get a raw byte data you do the following steps.
Get MemoryGroup of an image using GetPixelMemoryGroup() method.
Converting it into array (because GetPixelMemoryGroup() returns a interface) and taking first element (if somebody tells me why they did that, i'll appreciate).
From System.Memory<TPixel> get a Span and then do stuff in old way.
(i prefer solution from #Majid comment)
So the code looks something line this:
var _IMemoryGroup = image.GetPixelMemoryGroup();
var _MemoryGroup = _IMemoryGroup.ToArray()[0];
var PixelData = MemoryMarshal.AsBytes(_MemoryGroup.Span).ToArray();
ofc you don't have to split this into variables and you can do this in one line of code. I did it just for clarification purposes. This solution only viable as for 06 Sep 2020
I have to implement the below code in my Java application, but I am unable to find the jar file for HexUtils.bytesToHex(). Where do I find that?
byte[] data = cleartext.getBytes(ENCODING);
md.update(data);
byte[] digestedByteArray = md.digest();
// Convert digested bytes to 2 chars Hex Encoding
md5String = HexUtils.bytesToHex(digestedByteArray) );
Not sure that I got what does this code , but seems the same can be done with help of org.apache.commons.codec.binary.Hex.encodeHexString(final byte[] data) (commons-codec-*.jar). This one very easy to find
How to access integer data from a DataTable?
I do this to get a string:
tbEvent.Text = dt.Rows[0].Field<String>(0);
But this doesn't work:
int numb = dt.Rows[0].Field<Int>(0);
Regards,
Tea
int i = Convert.ToInt32(dt.Rows[0]["field_name"]);
Try this :-
tbEvent.Text = dt.Rows[0].Field<Int>(0).ToString();
I'm assuming your trying to pass the value to a Textbox.
Use strongly type access !
if your type is int ,
this
string g = dt.Rows[0].Field<String>(0);
will fail !
Unable to cast object of type 'System.Int32' to type 'System.String'
However if you know its int and you want to show its string represenation : ( or just ToString())
string t= dt.Rows[0].Field<int>(0).ToString();
or just : dt.Rows[0][0].ToString();
The Field extension method does not convert the type appropriate. It just simulates a strongly typed DataTable. So if you know that the type of the DataColumn is int it works this way:
int result = dt.Rows[0].Field<int>(0);
But if it actually comes as string you need to convert/parse it accordingly.
For example:
int result = int.Parse(dt.Rows[0].Field<String>(0));
or even more loosely typed (f.e. because it's a double or you don't know what it is)
int result = int.Parse(dt.Rows[0][0].ToString());