如何在Combobox中设置Selectedvalue c＃

Question

我有一个组合框，我已经设置了DataSource的值，但是当我尝试设置SelectedValue时，组合框返回null。所以请帮助。

BindingList<KeyValuePair<string, int>> m_items = 
        new BindingList<KeyValuePair<string, int>>(); 

for (int i = 2; i <= 12; i++) 
    m_items.Add(new KeyValuePair<string, int>(i.ToString(), i)); 
ComboBox cboGridSize = new ComboBox(); 
cboGridSize.DisplayMember = "Key"; 
cboGridSize.ValueMember = "Value"; 
cboGridSize.DataSource = m_items; 

cboGridSize.SelectedValue = 4; 

当我将SelectedValue设置为4时，它返回NULL。

Answer 1

同意@Laazo更改为字符串。

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或财产以后类似这样的

int selectedIndex = comboBox1.SelectedIndex; 
Object selectedItem = comboBox1.SelectedItem; 

MessageBox.Show("Selected Item Text: " + selectedItem.ToString() + "\n" + 
"Index: " + selectedIndex.ToString()); 

，并指这看起来好像将有利于您的问题：

• https://msdn.microsoft.com/en-us/library/system.windows.forms.combobox.selecteditem(v=vs.110).aspx
• How do I set the selected item in a comboBox to match my string using C#?
• Getting selected value of a combobox