c# string padded now want it short - c#

So I have two string that were padded, but now I want them show and Trim() doesn't seem to want to do it.
String devicename = "".PadRight(100);
String deviceversion = "".PadRight(100);
bool isDeviceReady = capGetDriverDescriptionA(i, ref devicename, 100, ref deviceversion, 100);
later I use the strings like in the below:
Messagebox.show("Device Name="+devicename.Trim()+" , Device Version="+deviceversion.Trim());
All that is shown is "Device Name=name of the device"
Thoughts?

Why are you padding the strings at all? It looks like you are just filling the strings with spaces that will get replaced later by content, but judging from your question I don't see why this is necessary. What is wrong with just:
String devicename = "";
String deviceversion = "";
bool isDeviceReady = capGetDriverDescriptionA(i, ref devicename, 100, ref deviceversion, 100);

You could try using StringBuilder instead of string when calling an API function that returns a zero-terminated string. The behaviour you're getting probably follows from the fact that the API writes zero value at the end of the string (to terminate it), while .NET treats it as a normal string containing zero value.
Alternatively, look at this discussion, which suggests to annotate the parameter with [MarshalAs(UnmanagedType.LPWSTR)] attribute. Then the PInovke mechanism should take care of zero value at the end automatically.

In the end it was pretty simple. Tomas Petrick was on the right track. It, the string, returned was a null terminated (also called a zero-terminated) string. Then I just needed to remove the null terminator from the strings.
devicename = devicename.trim('\0');

Related

Split string with plus sign as a delimiter

I have an issue with a string containing the plus sign (+).
I want to split that string (or if there is some other way to solve my problem)
string ColumnPlusLevel = "+-J10+-J10+-J10+-J10+-J10";
string strpluslevel = "";
strpluslevel = ColumnPlusLevel;
string[] strpluslevel_lines = Regex.Split(strpluslevel, "+");
foreach (string line in strpluslevel_lines)
{
MessageBox.Show(line);
strpluslevel_summa = strpluslevel_summa + line;
}
MessageBox.Show(strpluslevel_summa, "summa sumarum");
The MessageBox is for my testing purpose.
Now... The ColumnPlusLevel string can have very varied entry but it is always a repeated pattern starting with the plus sign.
i.e. "+MJ+MJ+MJ" or "+PPL14.1+PPL14.1+PPL14.1" as examples.
(It comes form Another software and I cant edit the output from that software)
How can I find out what that pattern is that is being repeated?
That in this exampels is the +-J10 or +MJ or +PPL14.1
In my case above I have tested it by using only a MessageBox to show the result but I want the repeated pattering stored in a string later on.
Maybe im doing it wrong by using Split, maybe there is another solution.
Maybe I use Split in the wrong way.
Hope you understand my problem and the result I want.
Thanks for any advice.
/Tomas
How can I find out what that pattern is that is being repeated?
Maybe i didn't understand the requirement fully, but isn't it easy as:
string[] tokens = ColumnPlusLevel.Split(new[]{'+'}, StringSplitOptions.RemoveEmptyEntries);
string first = tokens[0];
bool repeatingPattern = tokens.Skip(1).All(s => s == first);
If repeatingPattern is true you know that the pattern itself is first.
Can you maybe explain how the logic works
The line which contains tokens.Skip(1) is a LINQ query, so you need to add using System.Linq at the top of your code file. Since tokens is a string[] which implements IEnumerable<string> you can use any LINQ (extension-)method. Enumerable.Skip(1) will skip the first because i have already stored that in a variable and i want to know if all others are same. Therefore i use All which returns false as soon as one item doesn't match the condition(so one string is different to the first). If all are same you know that there is a repeating pattern which is already stored in the variable first.
You should use String.Split function :
string pattern = ColumnPlusLevel.Split("+")[0];
...but it is always a repeated pattern starting with the plus sign.
Why do you even need String.Split() here if the pattern always only repeats itself?
string input = #"+MJ+MJ+MJ";
int indexOfSecondPlus = input.IndexOf('+', 1);
string pattern = input.Remove(indexOfSecondPlus, input.Length - indexOfSecondPlus);
//pattern is now "+MJ"
No need of string split, no need to use LinQ
String has a method called Split which let's you split/divide the string based on a given character/character-set:
string givenString = "+-J10+-J10+-J10+-J10+-J10"'
string SplittedString = givenString.Split("+")[0] ///Here + is the character based on which the string would be splitted and 0 is the index number
string result = SplittedString.Replace("-","") //The mothod REPLACE replaces the given string with a targeted string,i added this so that you can get the numbers only from the string

how to remove last part of string in c#

I was trying to remove last part of a string but failed.Here string named D:\software\VS2012\newtext.txt and i want to trim last section of string so here newtext.txt . I should get D:\software\VS2012 but how to do it in c#.When i tried it is removing all the string that has '\'. Here is what i did in c#
string str = #"D:\softwares\VS2012\newtext.txt";
str= str.Remove(str.IndexOf('\\'));
Console.WriteLine(str);
There is a premade function for this in the framework
string str = #"D:\softwares\VS2012\newtext.txt";
string path = System.IO.Path.GetDirectoryName(str);
(Reference)
Note that your original code does not work because you are removing from the first backslash, not the last. Substitute this line to make your code work
str = str.Remove(str.LastIndexOf('\\'));
Try using System.IO.Path.GetDirectoryName(string):
string dirname= System.IO.Path.GetDirectoryName(#"D:\softwares\VS2012\newtext.txt");
For removing a known portion of a string you can simply use the Replace.
In your case:
str = str.Replace("\\newtext.txt", ""); //this will give you the same result of the System.IO.Path.GetDirectoryName already suggested by gmiley, but it's more in a string context as per your question
Though if you want to remove the last part of a string by the last encounterd known character then the suggested "LastIndexOff('\')" method already suggested along with the Remove.
If you want to use a delimiter method, so depending on the delimiter character but not on the string format (in your case path format) the LastIndexOff(char) is the best option.
Although you could also split the string into an array and then rejoin the array after removing the last element:
var delmimter = '\\';
var strAy = str.Split(char);
str = String.Join('\\', strAy.SkipLast(1).ToArray());
With this method you don't need to rely on the existence of the delimiter char in the string and the result is always without the delimiter char at the end.
Besides, you can easily create an extension with the delimiter as a parameter.
We should check the existance of the char also
string str = #"D:\softwares\VS2012\newtext.txt";
int rstr = str.LastIndexOf('\\');
if (rstr>0) str= str.Remove(rstr);
Console.WriteLine(str);

GetPrivateProfileString without Trim?

Being that this application has evolved over the years, there are still some INI files. I have a class that reads entries using GetPrivateProfileString.
At the top of the class we see this:
[DllImport("kernel32")]
private static extern int GetPrivateProfileString(string section,
string key, string def, StringBuilder retVal,
int size, string filePath);
And it looks like there is a public method that looks something like this:
public string IniReadValue(string Section, string Key)
{
// If string greater than 254 characters (255th spot is null-terminator),
// string will be truncated.
const int capacity = 255;
StringBuilder temp = new StringBuilder(capacity);
int i = GetPrivateProfileString(Section, Key, "", temp,
capacity, this.m_Path);
return temp.ToString();
}
I recently noticed that GetPrivateProfileString trims it's data. Therefore, if my INI file has an entry like this:
SomeData= Notice the three trailing spaces at front and back of this sentence.
It will retrieve it like (notice that it's trimmed to the left and right - ignore quotes):
"Notice the three trailing spaces at front and back of this sentence."
I don't want it to Trim. Is that out of my control? INI files aren't allowed to have spaces after the equal sign (e.g. SomeData=)?
As pointed out in the comments, that is how the API works. If you can live with that, you can at least save some DllImport work by using for example this library/wrapper (includes source, just one file):
IniReader
You can use quotation marks to express your content, when read the content into a string,
you can easily to parse the content you want.
like this:
key = " content "
and you can add some code in Function IniReadValue.
Or You can put/get the message use base64 string, like this:
some-key = your-content-in-base64-string
and many char issues would not be your problem.
But this way is not good for read.

Remove last characters from a string in C#. An elegant way?

I have a numeric string like this 2223,00. I would like to transform it to 2223. This is: without the information after the ",". Assume that there will be only two decimals after the ",".
I did:
str = str.Remove(str.Length - 3, 3);
Is there a more elegant solution? Maybe using another function? -I donĀ“t like putting explicit numbers-
You can actually just use the Remove overload that takes one parameter:
str = str.Remove(str.Length - 3);
However, if you're trying to avoid hard coding the length, you can use:
str = str.Remove(str.IndexOf(','));
Perhaps this:
str = str.Split(",").First();
This will return to you a string excluding everything after the comma
str = str.Substring(0, str.IndexOf(','));
Of course, this assumes your string actually has a comma with decimals. The above code will fail if it doesn't. You'd want to do more checks:
commaPos = str.IndexOf(',');
if(commaPos != -1)
str = str.Substring(0, commaPos)
I'm assuming you're working with a string to begin with. Ideally, if you're working with a number to begin with, like a float or double, you could just cast it to an int, then do myInt.ToString() like:
myInt = (int)double.Parse(myString)
This parses the double using the current culture (here in the US, we use . for decimal points). However, this again assumes that your input string is can be parsed.
String.Format("{0:0}", 123.4567); // "123"
If your initial value is a decimal into a string, you will need to convert
String.Format("{0:0}", double.Parse("3.5", CultureInfo.InvariantCulture)) //3.5
In this example, I choose Invariant culture but you could use the one you want.
I prefer using the Formatting function because you never know if the decimal may contain 2 or 3 leading number in the future.
Edit: You can also use Truncate to remove all after the , or .
Console.WriteLine(Decimal.Truncate(Convert.ToDecimal("3,5")));
Use:
public static class StringExtensions
{
/// <summary>
/// Cut End. "12".SubstringFromEnd(1) -> "1"
/// </summary>
public static string SubstringFromEnd(this string value, int startindex)
{
if (string.IsNullOrEmpty(value)) return value;
return value.Substring(0, value.Length - startindex);
}
}
I prefer an extension method here for two reasons:
I can chain it with Substring.
Example: f1.Substring(directorypathLength).SubstringFromEnd(1)
Speed.
You could use LastIndexOf and Substring combined to get all characters to the left of the last index of the comma within the sting.
string var = var.Substring(0, var.LastIndexOf(','));
You can use TrimEnd. It's efficient as well and looks clean.
"Name,".TrimEnd(',');
Try the following. It worked for me:
str = str.Split(',').Last();
Since C# 8.0 it has been possible to do this with a range operator.
string textValue = "2223,00";
textValue = textValue[0..^3];
Console.WriteLine(textValue);
This would output the string 2223.
The 0 says that it should start from the zeroth position in the string
The .. says that it should take the range between the operands on either side
The ^ says that it should take the operand relative to the end of the sequence
The 3 says that it should end from the third position in the string
Use lastIndexOf. Like:
string var = var.lastIndexOf(',');

C# Cannot implicitly convert type 'string' to 'string[]' within an if else statement

I am trying to read a string into an array and I get the error "Cannot implecitly convert type 'string' to 'string[]'.
The error occurs here:
string[] sepText = result.Tables[0].Rows[0].Field<string>("WebHTML").UrlDecode();
My full if else statement is below:
if (!string.IsNullOrEmpty(result.Tables[0].Rows[0].Field<string>("WebHTML")))
{
string[] sepText = result.Tables[0].Rows[0].Field<string>("WebHTML").UrlDecode();
NewsContent.Text = sepText[1];
if (!string.IsNullOrEmpty(sepText[0]))
Image1.ImageUrl = sepText[0];
else
Image1.Visible = false;
NewsTitle.Text = String.Format("{3}", Extensions.GetServerName(true), result.Tables[0].Rows[0].Field<int>("News_Item_ID"), result.Tables[0].Rows[0].Field<string>("Title").UrlFormat(), result.Tables[0].Rows[0].Field<string>("Title"));
Hyperlink1.NavigateUrl = String.Format("{0}/news/{1}/{2}.aspx", Extensions.GetServerName(true), result.Tables[0].Rows[0].Field<int>("News_Item_ID"), result.Tables[0].Rows[0].Field<string>("Title").UrlFormat());
}
else
{
Hyperlink1.Visible = false;
Image1.Visible = false;
}
Thank you for your help!
EDIT Code for URL Decode:
public static string UrlDecode(this string str)
{
return System.Web.HttpUtility.UrlDecode(str);
}
result.Tables[0].Rows[0].Field<string>("WebHTML") is going to give you the value of the WebHTML field in the first row in the first table which is a single string rather than a string[].
You may want to show your code for UrlDecode() since it looks like a custom implementation rather than one of the built-in framework versions.
You also declare the UrlDecode method to take a string as a parameter and return a string. Remember, a string is not the same thing as a string array.
It seems that you are trying to put:
result.Tables[0].Rows[0].Field<string>("WebHTML").UrlDecode();
which returns a string, into an array of strings.
Simply delare your sepText variable as a string rather than a string array and you should be good to go, e.g.:
string sepText = result.Tables[0].Rows[0].Field<string>("WebHTML").UrlDecode();
Later in your code you will clearly need to read the contents of the string like this:
Image1.ImageUrl =sepText;
Assuming the UrlDecode you are using is the one from here then the result is a string and not a string[] !
UrlDecode returns a string and you are assigning it to an array.
If you want the parts you will have to use the string to create an Url object.
Url url = new Url(result.Tables[0].Rows[0].Field<string>("WebHTML"));
and then get the parts.
See: Get url parts without host
I don't think URLDecode works the way you think it works. All URLDecode does is remove URL encoding from a string. It does not return an array of strings - only the decoded value of the string you gave it.
http://msdn.microsoft.com/en-us/library/system.web.httputility.urldecode.aspx
Example: Your web browser replaces a space with %20. This changes the %20 back to a space.
That's because the result of this line is "string" and you're trying to assign it to an array since UrlDecode do not produce an array. What you probably wanted is to use a method split() to create an array of separators?

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