Question

是否可以刷新组合框的项目并保留所选项目，以便不会触发SelectedIndexChanged事件？即使所选项目不在新项目列表中？

以下代码似乎会重置所选项目并触发SelectedIndexChanged事件。

void RefreshComboboxItems()
{
    var ds = GetRefreshedItems();
    cb.DataSource = ds;
    cb.DisplayMember = "Name";
    cb.ValueMember = "Value";
}

// cb is already initialized and an item is selected
RefreshComboboxItems(); // Want to keep the selected item unchanged and don't trigger the event

Answer 1

不，您可以获取当前的SelectedValue，删除事件处理程序，刷新组合，尝试再次使用保存的值设置SelectedValue，然后读取事件处理程序

void RefreshComboboxItems()
{
    try
    {
        int currentValue = -1;
        if(cb.SelectedValue != null) 
          currentValue = Convert.ToInt32(cb.SelectedValue);

       cb.SelectedIndexChanged -= mySelectedIndexChangedMethod;
       var ds = GetRefreshedItems();
       cb.DataSource = ds;
       cb.DisplayMember = "Name";
       cb.ValueMember = "Value";

       if(currentValue != -1)
         cb.SelectedValue = currentValue;

    }
    catch(Exception ex)
    {
       MessageBox.Show(ex.Message);
    }
    finally
    {
        cb.SelectedIndexChanged += mySelectedIndexChangedMethod;
    }
}

请注意，我已经在finally中读取了事件处理程序，以确保事件处理程序被重新读入组合框，以防异常导致在删除事件处理程序后过早退出此代码

Answer 2

如果您想暂时删除事件处理程序，可以执行以下操作：

void RefreshComboboxItems()
{
    cb.SelectedIndexChanged -= Ddl_SelectedIndexChanged;

    var ds = GetRefreshedItems();
    cb.DataSource = ds;
    cb.DisplayMember = "Name";
    cb.ValueMember = "Value";

    cb.SelectedIndexChanged += Ddl_SelectedIndexChanged;
}

从DataSource刷新ComboBox并保留所选项目，但不要触发SelectedIndexChanged

2 个答案: