组合框已清除后，该值（） [英] ComboBox has its old value after Clear()

问题描述

我有两个组合框 cb_Brand 和 cb_Model 上一个WinForm。

I have two comboBox cb_Brand and cb_Model on a winForm.

cb_Model 填充在品牌选择的值。 问题是：如果我们选择品牌任何和选择品牌下的任何模型， cb_Model 不松动的previous模式选择的值。 例如：如果我们选择了奥迪品牌和型号A3 和选择品牌的福特，当我点击 cb_Model 来选择模型，它显示了A3作为选择的模型，但在列表中仍然其他车型都属于福特。

cb_Model populates values on brand Select. the problem is: if we select the brand any and select the any model under that brand, cb_Model does not loose the value of previous model selected. for example: If we select the brand Audi and model A3 and the select the Brand Ford, when I click on cb_Model to select the model, it displayed the A3 as selected model, but still other models in list are belong to ford.

我的code是：

private void cb_Brand_SelectedIndexChanged(object sender, EventArgs e)
{
    // Clear Current Data
    cb_Model.Text = "";
    cb_Model.Items.Clear();

    CarModel _carmodel = new CarModel ();

    // Get Selected Car Brnad
    int CarBrandID = _carmodel .GetCarBrandID(cb_Brand.Text);

    //Enable choice of Model
    SortedList<int, Model> colM;

    colM = Model.ReadModel(CarBrandID);

    cb_Model.DisplayMember = "ModelText";
    foreach (Model objM in colM.Values)
    {
        cb_Model.Items.Add(objM);
    }
}

任何想法，请.. 谢谢

Any Idea Please.. Thanks

无法找到原因，但整理出来了临时修复：

unable to find the reason but sorted out with a temp fix:

private void cb_Model_Click(object sender, EventArgs e)
{
    cb_Model.Text = "";
}

非常感谢球员 欢呼声

Thanks a lot guys cheers

推荐答案

foreach (Model objM in colM.Values)
{
    cb_Model.Items.Add(objM);
}

让.NET照顾它为你和它与此替换：

Let .NET take care of it for you and replace it with this:

cb_Model.DataSource = colMValues;

这将数据绑定到列表并automatcially刷新组合框的物品时的数据源被设置

Which will bind the data to the list and refreshes the comboboxes items automatcially when a data source is set.

您也将不再需要这些行：

You will also not need these lines anymore:

// Clear Current Data
cb_Model.Text = "";
cb_Model.Items.Clear();

对此有阅读有关绑定列表的详细信息（和其他数据源），以组合框​​：

Have a read of this for more info on binding lists (and other data sources) to ComboBoxes:

如何：绑定Windows窗体组合框或列表框控件数据（MSDN）

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