Hi I am New to C# and could do with some help. I have a programme that currently save`s Events to there own text file which contains the details about the event(the details are entered by the user). One of these details is The Amount Of tickets. I am having trouble with making it so that when a ticket is brought the amount decreases by one.
I would like to Know If there Is Anyway For me to subtract 1 from a Number that is on a Text File. this is how my Text Files Are laid out:
Event Name: Test
Event Time: 12:30
Event Location: Test
Amount Of Tickets: 120
Price Of Tickets: £5
This is the method i tried and all this did was add -1 -1 to the value instead of taking away from the value:
Console.WriteLine("What Event Would You Like To Buy A Ticket For?");
string EventUpdate = Console.ReadLine();
string folderPath = (@"A:\Work\Visual Studio\TextFiles");
string fileName = EventUpdate + ".txt";
string filePath = folderPath + "\\" + fileName; //creats file path using FolderPath Plus users Input
string Contents = File.ReadAllText(filePath);
Console.WriteLine(Contents); //displays the txt file that was called for
Console.WriteLine("\n");
string FindText = "Amount Of Tickets:";
int I = -1;
string NewText = FindText + I;
string NewTempFile = folderPath + EventUpdate + ".txt";
string file = filePath;
File.WriteAllText(file, File.ReadAllText(file).Replace(FindText, NewText));
using (var sourceFile = File.OpenText(file))
{
// Create a temporary file path where we can write modify lines
string tempFile = Path.Combine(Path.GetDirectoryName(file), NewTempFile);
// Open a stream for the temporary file
using (var tempFileStream = new StreamWriter(tempFile))
{
string line;
// read lines while the file has them
while ((line = sourceFile.ReadLine()) != null)
{
// Do the Line replacement
line = line.Replace(FindText, NewText);
// Write the modified line to the new file
tempFileStream.WriteLine(line);
}
}
}
// Replace the original file with the temporary one
File.Replace(NewTempFile, file, null);
this is what happened to my text file when i used the above code:
Event Name: Test
Event Time: 12:30
Event Location: Test
Amount Of Tickets:-1-1 120
Price Of Tickets: £5
There are oodles of way to do this... However, you need to convert a your "text number" to an actual number (in this case an integer) to perform mathematical operations on it
// get the lines in an array
var lines = File.ReadAllLines(file);
// iterate through every line
for (var index = 0; index < lines.Length; index++)
{
// does the line start with the text you expect?
if (lines[index].StartsWith(findText))
{
// awesome, lets split it apart
var parts = lines[index].Split(':');
// part 2 (index 1) has your number
var num = int.Parse(parts[1].Trim());
// recreate the line minus 1
lines[index] = $"{findText} {num-1}";
// no more processing needed
break;
}
}
// write the lines to the file
File.WriteAllLines(file, lines);
Note : even if this doesn't work (and i haven't checked it) you should have enough information to continue unaided
Additional Resources
Determines whether the beginning of this string instance matches a specified string.
Returns a string array that contains the substrings in this instance that are delimited by elements of a specified string or Unicode character array.
Returns a new string in which all leading and trailing occurrences of a set of specified characters from the current String object are removed.
Converts the string representation of a number to its 32-bit signed integer equivalent.
Opens a text file, reads all lines of the file into a string array, and then closes the file.
Creates a new file, writes one or more strings to the file, and then closes the file.
$ - string interpolation (C# Reference)
The $ special character identifies a string literal as an interpolated string. An interpolated string is a string literal that might contain interpolated expressions. When an interpolated string is resolved to a result string, items with interpolated expressions are replaced by the string representations of the expression results. This feature is available in C# 6 and later versions of the language.