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Gets or sets the angle of the gradient fill for the specified fill format.
Use this property to get or set the direction of a gradient that has been applied to the fill.
double GradientAngle { get; set; }
Property GradientAngle As Double
IShape shape = worksheet.Shapes.AddShape(AutoShapeType.Rectangle, 20, 20, 100, 60);
IFillFormat fillFormat = shape.Fill;
fillFormat.TwoColorGradient(GradientStyle.Horizontal, 1);
fillFormat.GradientAngle = 45;
double angle = fillFormat.GradientAngle;