连接的服务属性应该导致数据源 [英] Connected service property should lead to datasource

问题描述

大家好，



我有连接服务并使用属性从EF6检索数据。

在测试应用程序中，我可以创建带有这些属性名称的列表，用于填充组合框

Hi everyone,

I have a connected services and use properties to retrieve data from EF6.
In a testapplication I can create a list with these propertyname to fill a combobox

ConnectedDataServices.DataServiceContext.GetType().GetRuntimeProperties().Select(x => x.Name).ToList();

我可以从他的属性获取vales但是作为类型对象而不是原始类型ConcurrentBag<> ;.



但是如何获取对象的内容或值来绑定所需的concurrentbag？



我尝试了什么： < br $>

I can get the vales from he property but as type object instead of the original type ConcurrentBag<>.

But how do I get the contents or values of the object to bind the concurrentbag desired?

What I have tried:

var selectedProp = comboBox1.SelectedItem.ToString();

            PropertyInfo propInfo = _availableProps.FirstOrDefault(x => x.Name == selectedProp);
            var results = propInfo.GetValue(ConnectedDataServices.DataServiceContext, null);
            Type type = results.GetType();
            dataGridView1.DataSource = results;
            dataGridView1.Refresh();

结果现在是对象类型而不是ConcurrentBag< entity>

results is now object type instead of ConcurrentBag<entity>

推荐答案

如果您使用的是最新版本的C＃编译器，则可以使用模式匹配开关来确保属性值的类型正确：

If you're using a recent version of the C# compiler, you can use a pattern-matching switch to make sure the property value is of the correct type:

switch (results)
{
    case null:
    case IList _:
    case IListSource _:
    {
        // Includes IBindingList and IBindingListView
        dataGridView1.DataSource = results;
        break;
    }
    case ICollection collection:
    {
        dataGridView1.DataSource = new ArrayList(collection);
        break;
    }
    case IEnumerable sequence:
    {
        dataGridView1.DataSource = sequence.Cast<object>().ToList();
        break;
    }
    default:
    {
        // Not a supported type:
        dataGridView1.DataSource = null;
        break;
    }
}

将它转换为在较旧的编译器中工作会很简单，但它不会像干净。：）

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