c# - 无效的转换异常未处理

Question

我想尝试在函数内部调用一个事件，而我想调用的事件是DataGridViewCellEventArgs，但它在函数内部。但是，当我尝试下面的代码时，我得到了这个错误：Unable to cast object of type 'System.Windows.Forms.MouseEventArgs' to type 'System.Windows.Forms.DataGridViewCellEventArgs'.

这是代码：

private void UpdateQuantityDataGridView(object sender, EventArgs e)
        {

           (...Other codes)
           var _productCode = dataGridView1["Product Code", ((DataGridViewCellEventArgs)e).RowIndex].Value;
           (...Other codes)

        }

当用户完成编辑数据DataGridView并按下“确定”按钮时，我调用上面的函数，上面的函数是更新用户对数据库以及 DataGridView 所做的任何更改

Answer 1

You are trying to cast EventArgs(parent type) to DataGridViewCellEventArgs(child type). This is not safe at this scenario. You can create a new DataGridViewCellEventArgs.

var _productCode = dataGridView1["Product Code",(new DataGridViewCellEventArgs(columnIndex, rowIndex)).RowIndex].Value;

Here a new DataGridViewCellEventArgs is created. Since it is a Event argument for a cell related action a columnIndex and rowIndex is needed to locate the cell.