Hi Aneesh,
You can change the css class properties once the DOM elements are created. However, there are no hook method which can help you with this.
Hence, another approach could be overriding the css style by adding the following piece of code in default.css in your project and referring to it.
.sapVizChart .v-gridline {
stroke: #FFFFFF !important;
}
I verified this, and it works. However, some drawbacks with this approach. The style will get applied to any UI5 visualization object which uses this style class. Also the color needs to be hard-coded (ideally to hide grid-lines would mean grid-lines have same color as chart background)
Thus I think i5SPCChart should have grid-line color configurable.
Best Regards,
Ria