class getData extends React.Component {

    constructor(props) {
        super(props);
    }

    getValue(p1,p2,p3) {
        ....
    }

    render() {

        var dropdown = <ul id="dropD"></ul>

        return (
            {dropdown}
        )
    }
}

<li onClick=this.getValue('x','xx','xxx')>value 1</li>
<li onClick=this.getValue('x','xx','xxx')>value 2</li>
<li onClick=this.getValue('x','xx','xxx')> ... </li>