How to automatically change chart on page after source data changed

[by0717]

I am a newcomer. How can I automatically update the page chart when the data source changes while using Altair charts, without relying on triggering components like buttons?"
case1: i have a pd.datafrme and show bar chart and line chart on page. And how to do it? I not found on chart department have this funtion : on_data_change
case2： i read a csv file and get the data. After i change the csv data how can the chart get the new data?