How to store the contents of a text file in NET to DataSet

Preface

Project on the text file operation is relatively simple, but if you need to write the contents of the text file in the system cache, the operation, will be a little tedious 1. Now summarize a more general method to cache the contents of text files into DataSet datasets. Not much to say below, let's look at the sample code directly.

Sample code

  private DataSet _iifSet;

  /// <summary>
  ///  Convert a text file to DataSet
  /// </summary>
  /// <param name="filePath"></param>
  /// <returns></returns>
  public DataSet Parse(string filePath)
  {
 　　　　　　　　 if (string.IsNullOrEmpty(filePath))
 　　　　　　　　 {
  　　　　　　　　 　　 throw new ArgumentNullException(filePath);
 　　　　　　　　 }

try
   {
    _iifSet = new DataSet();
    var fileText = System.IO.File.ReadAllText(filePath);
    var lines = fileText.Split('\n');
    CreateTables(lines, _iifSet);
    FillSet(lines, _iifSet);
    return _iifSet;
   }
   catch (IOException ex)
   {
    throw new IOException(ex.Message);
   }
   
  }

  /// <summary>
  ///  A table that reads an array of rows and parses it into a dataset 
  /// </summary>
  /// <param name="lines">String iif Array of rows in a file </param>
  /// <param name="set"></param>
  private void FillSet(IReadOnlyList<string> lines, DataSet set)
  {
   for (var i = 0; i < lines.Count; i++)
   {
    if (IsTableHeader(lines[i]))
    {
     continue;
    }
    if (lines[i] == "" || lines[i] == "\r" || lines[i] == "\n\r" || lines[i] == "\n")
    {
     continue;
    }
    if (lines[i].IndexOf(";__IMPORTED__", StringComparison.Ordinal) != -1)
    {
     continue;
    }
    var line = lines[i];
    while (!IsFullLine(line, set))
    {
     i++;
     line += lines[i];
    }
    ParseRecord(line, set);
   }
  }

  /// <summary>
  ///  Parse records 
  /// </summary>
  /// <param name="line"></param>
  /// <param name="set"></param>
  private void ParseRecord(string line, DataSet set)
  {
   if (IsTableHeader(line))
   {
    return;
   }
   var tablename = line.Split('\t')[0];
   var parameters = CreateDataRowParams(line, set.Tables[tablename].Columns.Count);
   if (parameters.Length > 0)
    set.Tables[tablename].Rows.Add(parameters);
  }

  private bool IsFullLine(string line, DataSet set)
  {
   if (IsTableHeader(line))
   {
    return true;
   }
   var values = line.Split('\t').Length;
   var tableName = line.Split('\t')[0];
   var columns = set.Tables[tableName].Columns.Count;
   return values >= columns;
  }

  private bool IsTableHeader(string tab)
  {
   return tab.StartsWith("!");
  }


  /// <summary>
  ///  Create datatable
  /// </summary>
  /// <param name="lines"></param>
  /// <param name="set"></param>
  private void CreateTables(IReadOnlyList<string> lines, DataSet set)
  {
   foreach (var t in lines.Where(IsTableHeader))
   {
    set.Tables.Add(CreateTable(t));
   }
  }


  private DataTable CreateTable(string line)
  {
   var values = line.Split('\t');
   values[0] = values[0].Substring(1);
   var dt = new DataTable(values[0]);
   values[0] = null;
   foreach (var name in values)
   {
    if (string.IsNullOrEmpty(name))
     continue;
    var dc = new DataColumn(name, typeof(string));
    try
    {
     dt.Columns.Add(dc);
    }
    catch (DuplicateNameException)
    {
     dc = new DataColumn(name + "_duplicateCol" + dt.Columns.Count);
     dt.Columns.Add(dc);
    }
   }

   return dt;
  }

  public string GetTableName(string line)
  {
   var values = line.Split('\t');
   if (values[0].StartsWith("!"))
   {
    values[0] = values[0].Substring(1);
   }
   return values[0];
  }

  public readonly static object[] EmptyStringArray = { };

  private object[] CreateDataRowParams(string line, int maxLength)
  {
   var raw = line.Split('\t');
   var length = raw.Length - 1;
   if (length == 0 || maxLength == 0)
    return EmptyStringArray;
   if (length > maxLength)
    length = maxLength;
   var values = new string[length];
   for (var i = 0; i < length; i++)
   {
    values[i] = raw[i + 1];
   }

   if (values[values.Length - 1].EndsWith("\n"))
   {
    values[values.Length - 1] = values[values.Length - 1].Substring(0, values[values.Length - 1].LastIndexOf('\n'));
   }
   else if (values[values.Length - 1].EndsWith("\n\r"))
   {
    values[values.Length - 1] = values[values.Length - 1].Substring(0, values[values.Length - 1].LastIndexOf("\n\r", StringComparison.Ordinal));
   }
   else if (values[values.Length - 1].EndsWith("\r"))
   {
    values[values.Length - 1] = values[values.Length - 1].Substring(0, values[values.Length - 1].LastIndexOf('\r'));
   }

   return values;
  }

  protected virtual void Dispose(bool cleanAll)
  {
   _iifSet?.Dispose();
  }

  public void Dispose()
  {
   Dispose(true);
   GC.SuppressFinalize(this);
  }

Summarize

Ok, this is the end of this article. Some common operations, basic attributes and methods of dataset will not be introduced here. I hope the content of this article can bring 1 certain help to everyone's study or work.