Passing a hex string in a textbox.text property to BitConverter.GetBytes as hex in C#

Question

I am reading values from sensors and receiving two 16 bit Hex values back in string format "417D" and "8380" for example.

I cannot seem to find a way in C# to parse the strings to split them up into a byte array ( 41,7D,83,80 ) preserving the hex number.

I then use the following to convert the IEEE754 number to a decimal to get the correct sensor reading value.

txtFloatValue.Text = BitConverter.ToSingle(hex, 0).ToString();

The code below works, but I need to pass the values as a hex array, not 0x417D8380.

byte[] hex = BitConverter.GetBytes(0x417D8380);
txtFloatValue.Text = BitConverter.ToSingle(hex, 0).ToString();

Any advice would be much appreciated. I may be approaching this the wrong way, but the IEEE754 conversion works well.

Not entirely sure what you are starting with and where you are trying to go, but you can parse a hex string with `int.Parse("417D", NumberStyles.AllowHexSpecifier);` You can then use `GetBytes` and `BitConverter` as in your second code snippet. — Matt Burland, Jan 05 '16 at 16:08
Hexadecimal is a **representation**. What do you mean by "preserving the hex number"? What _exactly_ is your question? _"How to convert two hexadecimal strings to a `single`"_? — CodeCaster, Jan 05 '16 at 16:20

score 1 · Accepted Answer · answered Jan 05 '16 at 16:12

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You can parse your hex strings to ints and then use BitConverter. For example:

var i = int.Parse("417D8380", NumberStyles.AllowHexSpecifier);
var bytes = BitConverter.GetBytes(i);
var single = BitConverter.ToSingle(bytes, 0);   // 15.8446

answered Jan 05 '16 at 16:12

Matt Burland

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Upvoted. The first line can also be written `var i = Convert.ToInt32("417D8380", fromBase: 16);` – Jeppe Stig Nielsen Jan 05 '16 at 16:20
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When concatenating `"417D"` and `"8380"`, one must be aware of endianness, I suspect. – Jeppe Stig Nielsen Jan 05 '16 at 16:21
@JeppeStigNielsen: Absolutely. You can check [BitConverter.IsLittleEndian](https://msdn.microsoft.com/en-us/library/system.bitconverter.islittleendian(v=vs.110).aspx). – Matt Burland Jan 05 '16 at 16:46

Passing a hex string in a textbox.text property to BitConverter.GetBytes as hex in C#

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