Please see the Screenshot. I need to draw this line as a straight line. This line gets updated after each point is added to the chart.

Screenshot 1 is implemented using IgniteUI and Screenshot 2 is using Infragistics Silverlight control. Could you please help me to draw this line as a straight line in IgniteUI (Screenshot 1)

I'm not sure I'm picturing what you mean appropriately. Could you sketch on the screenshot of that series to show what you mean?

Please find below my code. I have 3 Scatter series and one Line series in my chart. I need to show a line at the end of the scatter series just like Value Overlay in Infragistics Silverlight chart control.

function createScatterChart(selector, dataSource) {

$(selector).igDataChart({
width: "400px",
height: "700px",
dataSource: dataSource,
crosshairVisibility:"hidden",
title: "",
axes: [{
name: "xAxis",
type: "numericX",
interval: 10,
maximumValue: 100,
minimumValue: 0,
title: "",
},
{
name: "yAxis",
type: "numericY",
title: "",
isInverted: "true",
maximumValue: 1000,
minimumValue: 0,
interval: 100,
},
{
type: "categoryX",
name: "lineX",
labelVisibility: "collapsed", // do not display labels
majorStroke: "rgba(0, 0, 0, 0)" // transparent
}],
series: [{
name: "scatter1",
type: "scatter",
xAxis: "xAxis",
yAxis: "yAxis",
isHighlightingEnabled: true,
xMemberPath: "X1",
yMemberPath: "Y1",
markerType: "circle",
ID: "ID",

},
{
name: "scatter2",
type: "scatter",
xAxis: "xAxis",
yAxis: "yAxis",
xMemberPath: "X2",
yMemberPath: "Y2",
markerType: "circle",
ID: "ID",
isHighlightingEnabled: true,
},
{
name: "scatter3",
type: "scatter",
xAxis: "xAxis",
yAxis: "yAxis",
xMemberPath: "X3",
yMemberPath: "Y3",
markerType: "circle",
ID: "ID",
isHighlightingEnabled: true,
},
{
type: "line",
name: "lineSeries",
xAxis: "lineX",
yAxis: "yAxis",
valueMemberPath: "val",
brush: "red",
thickness: 4,
}
],

horizontalZoomable: true,
verticalZoomable: true,
windowResponse: "immediate"
});

I am updating my datasource using the below code:

$("#chartScatter").igDataChart("addItem", {"ID": FlawDataRecieved.FlawID, "X3": Yvalue, "Y3":FlawDataRecieved.Length,"val":FlawDataRecieved.Length});

Could you please help me.

do you mean you want the line to slide across the view? One way to do this itl is to remove point from the start of the series as you add them to the end.

THanks a lot for the explanation.

I have another issue. I need to draw a line with both the ends moving. The line series can move only one side. How to reset the start point of a line series dynamically

Could you please help me to solve my issue.