c# - DataGrid foreach 实体错误

Question

在这个 _ControlAvailable 中我遇到了一个错误。在我的实体“InsuranceQuotation c”(这是我的 db GridView)中，我可以访问“c.mYear”，这是一个包含日期的列。这来自 db 给我这样的“InsuranceQuotation.mYear”:

void EditableCustomersGrid_ControlAvailable(object sender, ControlAvailableEventArgs e)
    {
        List<int> ageList = new List<int>();
        if (e.Control is DataGrid)
        {
            DataGrid dg = (DataGrid)e.Control;

            // error here "InsuranceQuotation c"
            foreach (InsuranceQuotation c in dg.ItemsSource)
            {
                var yom = c.mYear;
                var bday = Convert.ToDateTime(yom);

                DateTime today = DateTime.Today;
                int age = today.Year - bday.Year;
                if (bday > today.AddYears(-age)) age--;

                ageList.Add(age);
            }
        }
    }

我在运行时遇到的错误是:

Unable to cast object of type 'Microsoft.LightSwitch.Presentation.Framework.NewItemPlaceholderDataContext' to type 'LightSwitchApplication.InsuranceQuotation'.

Answer 1

试试这个修复

void EditableCustomersGrid_ControlAvailable(object sender, ControlAvailableEventArgs e)
{
     List<int> ageList = new List<int>();
     if (e.Control is DataGrid)
     {
        DataGrid dg = (DataGrid)e.Control;
        IList rows = dg.ItemsSource.ToList();//this line lets you get the datagrid rows in Ilist 
        foreach (DataRowView c in rows )
        {
             var yom = c["mYear"];
             var bday = Convert.ToDateTime(yom);
             DateTime today = DateTime.Today;
             int age = today.Year - bday.Year;
             if (bday > today.AddYears(-age)) age--;
                ageList.Add(age);
        }
    }
}