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Definition Types
Updated on May 7, 2026
You can visualize the data differently based on the heat map definition. There are two main definition types - Categorical and Horizontal/Vertical.
CategoricalDefinition
Used to group the data by rows and columns. It has a single colorizer (HeatMapGradientColorizer with two GradientStops) for all content cells. The cells are colorized by their value which is extracted from the ValueMember field. The CategoricalDefinition requires the following properties to be setup for proper data binding:
- ColumnGroupMember: Gets or sets the name of the property which determines the column-category of a cell.
- RowGroupMember: Gets or sets the name of the property which determines the row-category of a cell.
- ValueMember: Gets or sets the name of the property which determines the value of a cell.
- DataSource: Specifies the data collection.
C#
DataTable countryInfoTable = new DataTable();
countryInfoTable.Columns.Add("Country", typeof(string));
countryInfoTable.Columns.Add("Year", typeof(int));
countryInfoTable.Columns.Add("HDI", typeof(float));
countryInfoTable.Rows.Add("Malta", 1985, 0.720);
countryInfoTable.Rows.Add("Italy", 1990, 0.764);
countryInfoTable.Rows.Add("Spain", 2000, 0.839);
countryInfoTable.Rows.Add("Italy", 2000, 0.825);
countryInfoTable.Rows.Add("Luxembourg", 1995, 0.816);
CategoricalDefinition categoricalDefinition1 = new CategoricalDefinition();
categoricalDefinition1.ColumnGroupMember = "Year";
categoricalDefinition1.DataSource = countryInfoTable;
categoricalDefinition1.RowGroupMember = "Country";
categoricalDefinition1.ValueMember = "HDI";
this.radHeatMap1.Definition = categoricalDefinition1;
HorizontalDefinition
Each column is represented by a MemberMapping. The latter has Header, ValueMember and Colorizer properties that allow you to have different value members and colorizer for each column of data. The default Colorizer created for the MemberMapping is a HeatMapGradientColorizer with two GradientStops.
C#
DataTable institutionTable = new DataTable();
institutionTable.Columns.Add("Name", typeof(string));
institutionTable.Columns.Add("SmartRank", typeof(double));
institutionTable.Columns.Add("AcceptanceRate", typeof(double));
institutionTable.Columns.Add("AverageSATMathScore", typeof(double));
institutionTable.Rows.Add("Harvard University", 1, 8, 27594);
institutionTable.Rows.Add("Princeton University", 2, 10, 7724);
institutionTable.Rows.Add("Yale University", 3, 10, 11701);
institutionTable.Rows.Add("California Institute of Technology", 4, 17, 2175);
institutionTable.Rows.Add("Massachusetts Institute of Technology", 5, 12, 10566);
HorizontalDefinition horizontalDefinition1 = new HorizontalDefinition();
horizontalDefinition1.DataSource = institutionTable;
horizontalDefinition1.HeaderMember = "Name";
radHeatMap1.Definition = horizontalDefinition1;
radHeatMap1.DescriptionContent = "Institution";
radHeatMap1.RowHeaderWidth = 250;
MemberMapping memberMapping1 = new MemberMapping();
memberMapping1.Header = "Smart Rank";
memberMapping1.ValueMember = "SmartRank";
MemberMapping memberMapping2 = new MemberMapping();
memberMapping2.Header = "Acceptance Rate (%)";
memberMapping2.ValueMember = "AcceptanceRate";
MemberMapping memberMapping3 = new MemberMapping();
memberMapping3.Header = "AVG SAT Math Score";
memberMapping3.ValueMember = "AverageSATMathScore";
horizontalDefinition1.MemberMappings.Add(memberMapping1);
horizontalDefinition1.MemberMappings.Add(memberMapping2);
horizontalDefinition1.MemberMappings.Add(memberMapping3);
VerticalDefinition
It is like the horizontal definition, but here the MemberMappings are oriented by rows.
C#
DataTable institutionTable = new DataTable();
institutionTable.Columns.Add("Name", typeof(string));
institutionTable.Columns.Add("SmartRank", typeof(double));
institutionTable.Columns.Add("AcceptanceRate", typeof(double));
institutionTable.Columns.Add("AverageSATMathScore", typeof(double));
institutionTable.Rows.Add("Harvard University", 1, 8, 27594);
institutionTable.Rows.Add("Princeton University", 2, 10, 7724);
institutionTable.Rows.Add("Yale University", 3, 10, 11701);
institutionTable.Rows.Add("California Institute of Technology", 4, 17, 2175);
institutionTable.Rows.Add("Massachusetts Institute of Technology", 5, 12, 10566);
VerticalDefinition verticalDefinition1 = new VerticalDefinition();
verticalDefinition1.DataSource = institutionTable;
verticalDefinition1.HeaderMember = "Name";
radHeatMap1.Definition = verticalDefinition1;
radHeatMap1.DescriptionContent = "Institution";
radHeatMap1.RowHeaderWidth = 150;
MemberMapping memberMapping1 = new MemberMapping();
memberMapping1.Header = "Smart Rank";
memberMapping1.ValueMember = "SmartRank";
MemberMapping memberMapping2 = new MemberMapping();
memberMapping2.Header = "Acceptance Rate (%)";
memberMapping2.ValueMember = "AcceptanceRate";
MemberMapping memberMapping3 = new MemberMapping();
memberMapping3.Header = "AVG SAT Math Score";
memberMapping3.ValueMember = "AverageSATMathScore";
verticalDefinition1.MemberMappings.Add(memberMapping1);
verticalDefinition1.MemberMappings.Add(memberMapping2);
verticalDefinition1.MemberMappings.Add(memberMapping3);