计算 ReactJs 中 TextArea 中的字符数

我有一些东西正在尝试在 react 中实现，这是一个简单的功能，可以计算在文本区域中键入了多少个字符。

这是源代码

var WordCount = React.createClass({
getInitialState: function() {
    return{ contacts: [], fullName: "What Ever", smsBalance: 0, command: 'Send Now', charsPerPage: 160, pageCount:0 };
},
wordCount: function(e){
    var currentText = e.target.value;
    //Now we need to recalculate the number of characters that have been typed in so far
    var characterCount = currentText.length;
    var charsPerPageCount = this.state.charsPerPage;
    var unitCount = Math.round(characterCount/charsPerPageCount);
    this.setState({pageCount: unitCount});
},
render: function() {
    return(
        <div className="md-card">

        <div className="user_content">
            <ul className="uk-margin">
                <div className="uk-margin-top">
                    <div className="uk-grid" data-uk-grid-margin="">
                        <div className="uk-width-medium-1-1">
                            <div className="md-input-wrapper">
                            <label htmlFor="Message">And Now Your Message</label>
                            <textarea className="md-input autosize_init" cols="30"
                                      data-val="true"
                                      data-val-required="The Message field is required."
                                      id="Message" ref="Message"
                                      rows="3" onChange={this.wordcount} style={{overflowX: "hidden", wordWrap: "break-word", height: 97+"PX"}}></textarea>
                            <span className="md-input-bar"></span></div>
                            <br/>
                            <span className="md-color-grey-300">
                                Current cost {this.state.pageCount}
                            </span>
                        </div>
                    </div>

                </div>
            </ul>
        </div>
        </div>
    );
}
});
ReactDOM.render(<WordCount/>, document.getElementById("PageContent"))

理想情况下，我打算实现的是计算用户到目前为止在文本区域中输入的字符数，并将该数字除以某个预设值以获得页数并向用户显示用户输入的页数

但是，sate 变量 'pageCount' 永远保持为零。请问我做错了什么

问候彼得