ComboBox项目为空，但数据源已满 [英] ComboBox Items Empty but DataSource Full

问题描述

将列表绑定到组合框后，其dataSource.Count为5，但是组合框项计数为0。
怎么可能？

我已经习惯了Web编程，这是Windows窗体。
因此不存在 combo.DataBind（）; 方法。

这里的问题是，我m尝试以编程方式设置所选项目。由于看不到combo.Items集合，因此无法设置所需的项目。

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Update

我需要完全更新：

• 数据源包含7个项目


• 绑定到组合框时， DisplayMember 和 ValueMember 得到适当实现


• 数据绑定后，通过gui，我可以清楚地看到组合框中的7个项目


• combobox.DataSource.Count = 7 和 combobox.Items.Count = 0

所以问题出在这里；因为数据绑定之后，组合框的ItemCollection中没有项目；我无法搜索要匹配的图像并设置合适的图像。

这里是一幅更好理解的图像（但是我很确定我很简单） / p>

解决方案

在 BindingSource <之前添加 ddl.BindingContext = new BindingContext（）; 之后/ code>分配，一切正常。

After binding a list to combobox, its dataSource.Count is 5 but, combobox item count is 0. how can it be?

I'm used to Web programming and this is in Windows Forms. So no combo.DataBind(); method exists.

The problem here is, I'm trying to set the selected item programmatically. Since I don't see the combo.Items collection filled, I cannot set the desired item.

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Update

A total update is needed I guess:

• datasource contains 7 items
• when bound to combobox, DisplayMember and ValueMember are appropriately implemented
• after databound, through the gui, I can clearly see the 7 items in the combobox
• combobox.DataSource.Count = 7 and combobox.Items.Count = 0

So the problem is here; since after databound no items are there in the ItemCollection of combobox; I cannot search for one to match and set the appropriate one.

Here is a image for better understanding (But I'm pretty sure I'm missing sth simple)

解决方案

After adding ddl.BindingContext = new BindingContext(); before the BindingSource assignment, everything worked fine.

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