您已经发现，WPF DataGrid没有Rows属性

尝试这样的操作:

As you have discovered, the WPF DataGrid does not have a Rows property

Try something like this:

foreach (System.Data.DataRowView dr in datagrid.ItemsSource)
{
    string t = dr[3].ToString();
    if (t =="research_Key")
    {
        MesssageBox.Show("ok");
    }
}

但是正如@ Richard-MacCutchan指出的那样-t只会是DataGrid中最后一行的字符串

But as @Richard-MacCutchan pointed out - t will only be the string from the last row in the DataGrid