Index: branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/Implementations/HistogramLogic.cs
===================================================================
--- branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/Implementations/HistogramLogic.cs	(revision 10551)
+++ branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/Implementations/HistogramLogic.cs	(revision 10552)
@@ -21,6 +21,89 @@
 
 
+using System;
+using System.Collections.Generic;
+using HeuristicLab.Analysis;
+
 namespace HeuristicLab.DataPreprocessing {
   public class HistogramLogic : IHistogramLogic {
+        private IPreprocessingData preprocessingData;
+    private DataTable dataTable;
+
+    public HistogramLogic(IPreprocessingData preprocessingData) {
+      this.preprocessingData = preprocessingData;
+      dataTable = new DataTable("Histogram");
+      FillDataTable();
+      preprocessingData.Changed += PreprocessingData_Changed;
+    }
+
+    private void FillDataTable() {
+      IEnumerable<string> variableNames = preprocessingData.VariableNames;
+
+      foreach (string variableName in variableNames) {
+        IList<double> values = preprocessingData.GetValues<double>(variableName);
+        DataRow row = new DataRow(variableName, "", values);
+        row.VisualProperties.ChartType = DataRowVisualProperties.DataRowChartType.Histogram;
+        dataTable.Rows.Add(row);
+      }
+
+    }
+
+    public IEnumerable<object> GetVariableNames() {
+      List<string> doubleVariableNames = new List<string>();
+
+      //only return variable names from type double
+      foreach (string variableName in preprocessingData.VariableNames) {
+        if (preprocessingData.IsType<double>(preprocessingData.GetColumnIndex(variableName)))
+          doubleVariableNames.Add(variableName);
+      }
+
+      return doubleVariableNames;
+    }
+
+    public DataTable GetDataTable() {
+      return dataTable;
+    }
+
+    public void RemoveVariable(string name) {
+      dataTable.Rows.Remove(name);
+    }
+
+    public void AddVariable(string name) {
+      IList<double> values = preprocessingData.GetValues<double>(name);
+      DataRow row = new DataRow(name, "", values);
+      row.VisualProperties.ChartType = DataRowVisualProperties.DataRowChartType.Histogram;
+      dataTable.Rows.Add(row);
+    }
+
+    public bool VariableIsDisplayed(string name) {
+
+      foreach (var item in dataTable.Rows) {
+        if (item.Name == name)
+          return true;
+      }
+      return false;
+    }
+
+    void PreprocessingData_Changed(object sender, DataPreprocessingChangedEventArgs e) {
+      var variableName = preprocessingData.GetVariableName(e.Column);
+      switch (e.Type) {
+        case DataPreprocessingChangedEventType.DeleteColumn:
+          dataTable.Rows.Remove(variableName);
+          break;
+        case DataPreprocessingChangedEventType.AddColumn:
+          dataTable.Rows.Add(new DataRow(variableName, String.Empty, preprocessingData.GetValues<double>(e.Column)));
+          break;
+        case DataPreprocessingChangedEventType.ChangeColumn:
+        case DataPreprocessingChangedEventType.ChangeItem:
+          dataTable.Rows.Remove(variableName);
+          dataTable.Rows.Add(new DataRow(variableName, String.Empty, preprocessingData.GetValues<double>(e.Column)));
+          break;
+        case DataPreprocessingChangedEventType.DeleteRow:
+        case DataPreprocessingChangedEventType.AddRow:
+          dataTable.Rows.Clear();
+          FillDataTable();
+          break;
+      }
+    }
   }
 }
Index: branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/Implementations/LineChartLogic.cs
===================================================================
--- branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/Implementations/LineChartLogic.cs	(revision 10551)
+++ branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/Implementations/LineChartLogic.cs	(revision 10552)
@@ -48,5 +48,13 @@
 
     public IEnumerable<object> GetVariableNames() {
-      return preprocessingData.VariableNames;
+      List<string> doubleVariableNames = new List<string>();
+
+      //only return variable names from type double
+      foreach (string variableName in preprocessingData.VariableNames) {
+        if (preprocessingData.IsType<double>(preprocessingData.GetColumnIndex(variableName)))
+          doubleVariableNames.Add(variableName);
+      }
+
+      return doubleVariableNames;
     }
 
@@ -54,7 +62,4 @@
       return dataTable;
     }
-
-
-    #region ILineChartLogic Members
 
     public void RemoveVariable(string name) {
@@ -67,6 +72,4 @@
       dataTable.Rows.Add(row);
     }
-
-    #endregion
 
     public bool VariableIsDisplayed(string name) {
