1. ItemMapping DataPointMember
I will try to explain bluntly. On one side you have your underlying business object (say Product which has properties - ProductId, Value, MinPrice, MaxPrice). On the other side you have the series definition (for instance BarSeriesDefinition or RangeBarSeriesDefinition). The item mapping is used to map a property of your business object to a series definition data point member. For example - you can map the ProductId to the XCategory and map the Value to the YValue of a bar series definition. You might instead want to map the ProductId to XValue and map the MinPrice to Low and MaxPrice to High for a RangeBarSeriesDefinition. So depending on what series definition you use you need to set the appropriate mappings. These can intuitively be extracted just from examining our examples here
2. I am not sure I fully understand you here. Yes, it is possible to map the X axis against dates. Yes, it is possible to control the format of the X axis labels. You can see this in the First Look Example of the link that I provided above. You can also read about the axis' features in our help topics here
3. Yes, there is only one group setting per series mapping but you can combine many group descriptors. But maybe in your scenario you will need to use several series instead.
I am sure that once you start building your app all will come in place. Make sure you examine our examples so that you get familiar with the chart's features, possibilities and limitations.
the Telerik team
Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>