Provide Graph ColorPalette Dynamically

Environment

Product

Progress® Telerik® Reporting

Description

The ColorPalette property does not support Expressions and its value can be set directly only to a constant value.

Solution

You may set the ColorPalette with Bindings:

Property Path   |   Expression
ColorPalette    |   = MyUserFunctionName(MyColor1, MyColor2, ...)

The above User Function should return an object of type Telerik.Reporting.Drawing.IColorPalette. A sample implementation in C# may look like:

public static IColorPalette UserColorPalette(params string[] hexColors)
{
    string[] colors = hexColors;

    if (null == colors || colors.Length <= 0)
    {
        return null;
    }

    if (colors.Length == 1)
    {
        colors = colors[0]
            .Split('#')
            .Where(c => !string.IsNullOrWhiteSpace(c))
            .Select(c => $"#{c.Trim()}")
            .ToArray();
    }

    ColorPalette colorPalette = new ColorPalette(colors);

    return colorPalette;
}

The above method may accept a list of string values, each holding a single hex color or a single string that contains one or more colors. In the latter case, it will split the colors by '#' and create and return an IColorPalette from them. Here is how you may use the method in the Binding Expression with each color provided separately:

= UserColorPalette("#FAFAFA", "#FF8080", "#80FF80")

and with all colors concatenated in a single string:

= UserColorPalette("#FAFAFA#FF8080#80FF80")

In both cases, you may add more colors.

If you use the Standalone designer it will be necessary to extend it with the function as explained in the Extending Report Designer article.