title: Declaring an instance variable for an OxyPlot graphing object
body: <p>I am using OxyPlot, a graphing library for C#. What confuses me so far is the <code>type</code> for some of the constructors. A code snippet is below:</p>
  
  <pre><code>public static PlotModel Notinterpolatedvalues() {
              var plotModel1 = new PlotModel();
              plotModel1.Subtitle = "Input text here";
  
              var linearColorAxis1 = new LinearColorAxis();
              linearColorAxis1.HighColor = OxyColors.Gray;
              linearColorAxis1.LowColor = OxyColors.Black;
              linearColorAxis1.Position = AxisPosition.Right;
              plotModel1.Axes.Add(linearColorAxis1);
  
              var linearAxis1 = new LinearAxis();
              linearAxis1.Position = AxisPosition.Bottom;
              plotModel1.Axes.Add(linearAxis1);
  
              var linearAxis2 = new LinearAxis();
              plotModel1.Axes.Add(linearAxis2);
  
              var heatMapSeries1 = new HeatMapSeries();
              heatMapSeries1.X0 = 0.5;
              heatMapSeries1.X1 = 1.5;
              heatMapSeries1.Y0 = 0.5;
              heatMapSeries1.Y1 = 2.5;
              heatMapSeries1.Interpolate = false;
  
              heatMapSeries1.Data = new Double[2, 3];
              heatMapSeries1.Data[0, 0] = 0;
              heatMapSeries1.Data[0, 1] = 0.2;
              heatMapSeries1.Data[0, 2] = 0.4;
              heatMapSeries1.Data[1, 0] = 0.1;
              heatMapSeries1.Data[1, 1] = 0.3;
              heatMapSeries1.Data[1, 2] = 0.2;
  
              plotModel1.Series.Add(heatMapSeries1);
              return plotModel1;
          }
  </code></pre>
  
  <p>This generates this image: </p>
  
  <p><img src="https://i.stack.imgur.com/ps82i.png" alt="enter image description here"></p>
  
  <p>(It's a heat map)</p>
  
  <p>My question is - what is <code>var</code>? For example, when you create a new multidimensional array, you do this:</p>
  
  <pre><code>double[,] doubleArray = new double[columns, rows];
  </code></pre>
  
  <p>Understandingly, the <code>type</code> for this is a <code>double[,]</code>. Why I need to know this is that I would like to store the heatmap as an instance variable, more specifically, <code>heatMapSeries1.Data</code> as a multi-dimensional array. However, in VS, I am unable to declare <code>var</code> as the type for an instance variable. The only selection I get is this:</p>
  
  <p><img src="https://i.stack.imgur.com/SmEPT.png" alt="enter image description here"></p>
  
  <p>Any OxyPlot pros in here could lend me a hand? Thank you.</p>