Save/Load ListBox/Read file text C#

//load
{
this.listBox1.Items.Clear();
OpenFileDialog Open = new OpenFileDialog();
Open.Filter = "Text Document|*.txt|All Files|*.*";
try
{
Open.ShowDialog();
StreamReader Import = new StreamReader(Convert.ToString(Open.FileName));
while (Import.Peek() >= 0)
listBox1.Items.Add(Convert.ToString(Import.ReadLin e()));
}
catch (Exception ex)
{
MessageBox.Show(Convert.ToString(ex.Message));
return;
}
}

//save
StreamWriter Write;
SaveFileDialog Open = new SaveFileDialog();
try
{
Open.Filter = ("Text Document|*.txt|All Files|*.*");
Open.ShowDialog();
Write = new StreamWriter(Open.FileName);
for (int I = 0; I < listBox4.Items.Count; I++)
{
Write.WriteLine(Convert.ToString(listBox4.Items[i]));
}
Write.Close();
}
catch (Exception ex)
{
MessageBox.Show(Convert.ToString(ex.Message));
return;
}