如何在填充了字典的组合框中获取 SelectedValue 的值

Question

We have dictionary like this:

var dictionary = new Dictionary<int, int> { { 0, 100 }, { 1, 202 }, { 2, 309 }, };

and so on a lot of values. dictionary binded to comboBox like this:

comboBox1.ItemsSource = dictionary;
comboBox1.DisplayMemberPath = "Value";

I'm wonder how can I get selectedvalue of this comboBox, if comboBox.Text works only for manually inputted values and this code:

string value = comboBox1.SelectedValue.ToString();

return value like [1, 202], while I need clear int TValue "202". I'm unable to find similar question so I ask it there and hope that the answer may be useful for someone else.

Answer 1

Looks like you have to cast SelectedValue into KeyValuePair<int, int> :

string value = ((KeyValuePair<int, int>)comboBox1.SelectedValue).Value.ToString();

However, you should put a brakepoint there and check what type SelectedValue really is.

I assume it's KeyValuePair<int, int> because your source collection is Dictionary<int, int> and because of output string for SelectedValue.ToString() which is [1, 202] .

Answer 2

If you specify the ValueMember, you can avoid the cast operation. It's important that you set the path before the datasource, or it will fire the changed event with a selected value that is a keyvaluepair.

comboBox1.DisplayMemberPath = "Value";
comboBox1.SelectedValuePath= "Key";
comboBox1.ItemsSource = dictionary;
string value = comboBox1.SelectedValue.ToString();