listview 全选有关问题

listview 全选问题
foreach (ListViewItem it in lvSourceChecInfo.Items)
  {
  it.Selected = true;
  }

怎么不能实现全选？

[解决办法]
1. this.listView1.MultiSelect = true;

2. 当焦点不在listView1时，选中的可能不显示．
　　设置: this.listView1.HideSelection = false;
[解决办法]
lvSourceChecInfo.MultiSelect = true;

lvSourceChecInfo.Focus();
foreach (ListViewItem it in lvSourceChecInfo.Items)
{
it.Selected = true;
}
[解决办法]

C# code

lvSourceChecInfo.MultiSelect = true;foreach (ListViewItem it in lvSourceChecInfo.Items)             {                 it.Selected = true;             }