This is a binary file which contains characters outside the set of printable ASCII characters.
Because these characters are "not printable", Notepad++ displays them as a descriptive block. You'll likely see others, as shown below. Here you see all of the values from binary 0 / 0x00 to 255 / 0xFF (which is the largest value that can be stored in a single byte).
The values shown on lines 1, 2 and 3 are typically referred to as "Control Characters", and are used to influence the terminal, cursor placement, etc... a NUL has the value 0 / 0x00. The BS control character is "Backspace", and instructs the application to remove one character and move the cursor back one space. Worthy of note are the "missing" or invisible characters between BS and VT... in here are the "Horizontal Tab" and "Line Feed" characters - the former is fairly self explanatory, and the latter will makes the text flow on to the next line.
On lines 4 and 5 you can see the entire set of printable ASCII characters. A space () has the binary values 32 / 0x20, an exclaimation point has the values 33 / 0x21, etc... The funny square box on the end of line 5 is the DEL control character - 127 / 0x7F.
All values including and above 128 are either "Extended ASCII", or also non-printable, and these are displayed from line 6 onwards as their raw value - e.g: x80. There isn't a good way to determine how to interpret these - some DOS applications used some of these characters to produce frames around "windows", boxes or areas on the terminal.
For more information, see the "Character Groups" section of the wiki page.
Viewing the same file as above in a "Hex Editor", you will typically see the raw binary values alongside the ASCII representation.
When the file contains data other than plain text (e.g: it's an application, or other binary file), you'll see a lot of non-print characters, because they were never intended for human consumption... In such files, the data is laid out in binary, usually following a strict structure or format. In some cases the data represents large numbers (by concatenating a number of bytes together), in other cases they might represent "machine code" or raw instructions that are presented directly to a processor.
You might be able to see strings inside such binary files, but this is more "by accident" than on purpose - the application itself has to know what to print to the screen when you see a message, and this will be that.
There are a couple of common ways that strings are encoded in binary files.
1. C String
This format makes use of 8-bit characters, and terminates the string with a NUL character. The string is immediately visible in the file, as shown below - note the terminating NUL.
2. UTF-16
This format makes use of 16-bit characters (i.e: two bytes concatenated), and can represent a portion of the code points described by Unicode. Here, you see that the string is somewhat visible, if you read between the NUL characters... This format is very common in applications that target Windows.
Can you see the string Logical Disks on the second line?
Binary files can also store other resources inside them - for example images, sounds, XML, JSON, Archives, etc... the application can then extract the resources to disk at runtime if necessary, or may often process them directly from memory.
It's often possible to extract these resources using tools in an automated fashion, but in some cases the file is not designed to an open / common standard, and some manual intervention is required.
When you create a file to store data, you can store a series of bytes. 1 byte is any number between 0 and 255. In many fileformats, it is enough to use any number between 0 and 255 to store data.
But as systems get more complex and advanced, developers sometimes need to store numbers that are far greater than 255. 2 bytes = 256*256 = 65535, 4 bytes = 256*256*256*256 = 4294967296. So by combining 4 bytes, one can store values from 0 to 4294967295.
You can even combine 8 or more bytes to form a number which often happens in 64-bit applications where you need 64 bits (8x8 bytes).
Because numbers stored are often low, most of the bytes are 0, aka NUL. So in a file, you see a lot of NUL because it are all low values in 64-bit constructions.
Why would one not optimize the file? Because most programmers use functions that store the data for them, and they keep every scenario in mind, including storing big numbers.
I remember what I was taught in college, but that was years ago. The professor at the time said to avoid it at all costs. I'm curious what the current consensus is.
Hey everyone,
Today I was received 2 text messages from my number that just said "null." This was right after I sent 2 text messages which seemed to go through just fine. I was wondering if anyone knows what this means? I recently blocked a number, so I'm not sure if that is related.
Thanks in advance!
Related to : SMS messages just have "null"
Try this,
delete their contact
then
Settings > Applications > Manage Applications > Select the Messaging App
Choose 'Clear Data' and also 'Clear Cache'.
N.B. you will lose all data / txt msg's in your phone
(don't forget to write their number down to save as new afterwards!)
You could also check on http://www.google.com/contacts and check if the address book entry for that person is missing some information.
So, for anyone that search this and got here, I'm using this to manage null String variables.
1. Show Empty Text
String nullText; //for null-safety change to: String? nullText;
//now, inside of your widget build
Text(nullText ?? '');
2. Not show Text Widget
String nullText;
//now, inside of your widget build
if(nullText != null)
Text(nullText);
with null-safety
String? nullText;
//now, inside of your widget build
if(nullText != null)
Text(nullText!);
Also you can show like this, but this show the null word
String nullText; //for null-safety change to String? nullText;
//now, inside of your widget build
Text('$nullText');
Live Example https://dartpad.dev/faab5bc3c2df9573c0a75a5ce3d4b4b9
It's not clear from the information your provided in your question what code causes the error, but I guess it is this line:
return Text(textvalue);
If you change it to
return textvalue != null ? Text(textvalue) : Container();
your error should go away.
You should probably be doing your check like this:
if (textBox_Results != null && !string.IsNullOrWhiteSpace(textBox_Results.Text))
Just an extra check so if textBox_Results is ever null you don't get a Null Reference Exception.
You should use String.IsNullOrEmpty(), if using .NET 4 String.IsNullOrWhitespace() to check .Text for Null values.
private void button_Click(object sender, EventArgs e)
{
if (!String.IsNullOrEmpty(textBox_Results.Text) Clipboard.SetText(textBox_Results.Text);
//rest of the code goes here;
}