Перевести выбранные элементы ListBox в строку

string str = string.Empty;
 
            if (lb.SelectedItems.Count == 0) return;
            foreach (string s in lb.SelectedItems)
                str += s + " ";
            dbgList.Text = str;

string str = "";
for(int i=0;i<lb.SelectedItems.Count;i++){str +=lb.SelectedItems[i]+" ";}

for(int i=0;i<lb.SelectedItems.Count;i++){dbgList.Text+=lb.SelectedItems[i]+" ";}

foreach (ListViewItem s in lb.SelectedItems)

for(int i=0;i<lb.SelectedItems.Count;i++){dbgList.Text+=lb.SelectedItems[i].Text+" ";}

for(int i=0;i<lb.SelectedItems.Count;i++){dbgList.Text+=lb.SelectedItems[i].Text+" ";}

var result = String.Join(" ", listBox.SelectedItems.Cast<string>());

foreach (ListBoxItem s in lb.SelectedItems)
     str += s.Content + " ";

var listBox = new System.Windows.Controls.ListBox();
var result = String.Join(" ", listBox.SelectedItems.Cast<System.Windows.Controls.ListBoxItem>().Select(x => x.Content));