从文本文件中读取特定的字符串

Question

I'm trying to get certain strings out of a text file and put it in a variable. This is what the structure of the text file looks like keep in mind this is just one line and each line looks like this and is separated by a blank line:

Date: 8/12/2013 12:00:00 AM Source Path: \\build\PM\11.0.64.1\build.11.0.64.1.FileServerOutput.zip Destination Path: C:\Users\Documents\.NET Development\testing\11.0.64.1\build.11.0.55.5.FileServerOutput.zip Folder Updated: 11.0.64.1 File Copied: build.11.0.55.5.FileServerOutput.zip

I wasn't entirely too sure of what to use for a delimiter for this text file or even if I should be using a delimiter so it could be subjected to change.

So just a quick example of what I want to happen with this, is I want to go through and grab the Destination Path and store it in a variable such as strDestPath.

Overall the code I came up with so far is this:

//find the variables from the text file
string[] lines = File.ReadAllLines(GlobalVars.strLogPath);

Yeah not much, but I thought perhaps if I just read one line at at a time and tried to search for what I was looking for through that line but honestly I'm not 100% sure if I should stick with that way or not...

Answer 1

If you are skeptical about how large your file is, you should come up using ReadLines which is deferred execution instead of ReadAllLines :

var lines = File.ReadLines(GlobalVars.strLogPath);

The ReadLines and ReadAllLines methods differ as follows:

When you use ReadLines, you can start enumerating the collection of strings before the whole collection is returned; when you use ReadAllLines, you must wait for the whole array of strings be returned before you can access the array. Therefore, when you are working with very large files, ReadLines can be more efficient.

Answer 2

As weird as it might sound, you should take a look to log parser. If you are free to set the file format you could use one that fits with log parser and, believe me, it will make your life a lot more easy.

Once you load the file with log parse you can user queries to get the information you want. If you don't care about using interop in your project you can even add a com reference and use it from any .net project.

This sample reads a HUGE csv file a makes a bulkcopy to the DB to perform there the final steps. This is not really your case, but shows you how easy is to do this with logparser

COMTSVInputContextClass logParserTsv = new COMTSVInputContextClass();
COMSQLOutputContextClass logParserSql = new COMSQLOutputContextClass();
logParserTsv.separator = ";";
logParserTsv.fixedSep = true;

logParserSql.database = _sqlDatabaseName;
logParserSql.server = _sqlServerName;
logParserSql.username = _sqlUser;
logParserSql.password = _sqlPass;
logParserSql.createTable = false;
logParserSql.ignoreIdCols = true;

// query shortened for clarity purposes
string SelectPattern = @"Select  TO_STRING(UserName),TO_STRING(UserID) INTO {0}  From {1}";

string query = string.Format(SelectPattern, _sqlTable, _csvPath);
logParser.ExecuteBatch(query, logParserTsv, logParserSql);

LogParser in one of those hidden gems Microsoft has and most people don't know about. I have use to read iis logs, CSV files, txt files, etc. You can even generate graphics!!!

Just check it here http://support.microsoft.com/kb/910447/en

Answer 3

Looks like you need to create a Tokenizer. Try something like this:

Define a list of token values:

List<string> gTkList = new List<string>() {"Date:","Source Path:" }; //...etc.

Create a Token class:

public class Token
{
  private readonly string _tokenText;
  private string _val;
  private int _begin, _end;

  public Token(string tk, int beg, int end)
  {
   this._tokenText = tk;
   this._begin = beg;
   this._end = end;
   this._val = String.Empty;
  }

  public string TokenText
  {
   get{ return _tokenText; }
  }

  public string Value
  {
   get { return _val; }
   set { _val = value; }
  }

  public int IdxBegin
  {
   get { return _begin; }
  }

  public int IdxEnd
  {
   get { return _end; }
  }
}

Create a method to Find your Tokens:

List<Token> FindTokens(string str)
{
 List<Token> retVal = new List<Token>();
 if (!String.IsNullOrWhitespace(str))
 {
  foreach(string cd in gTkList)
  {
    int fIdx = str.IndexOf(cd);
    if(fIdx > -1)
       retVal.Add(cd,fIdx,fIdx + cd.Length);
  }      
 }
 return retVal;
}

Then just do something like this:

foreach(string ln in lines)
{
 //returns ordered list of tokens
 var tkns = FindTokens(ln);
 for(int i=0; i < tkns.Length; i++)
 {
  int len = (i == tkns.Length - 1) ? ln.Length - tkns[i].IdxEnd : tkns[i+1].IdxBegin - tkns[i].IdxEnd;
  tkns[i].value = ln.Substring(tkns[i].IdxEnd+1,len).Trim();
 }

 //Do something with the gathered values
 foreach(Token tk in tkns)
 {
  //stuff
 }
}