怎么用通用对话框打开文件？

[null_name]

private void openFileDialog_FileOk(object sender, System.ComponentModel.CancelEventArgs e)
{
try
{
//我想通过openFileDialog在rtfTex中显示打开的文件，参 数怎么弄？
this.rtfText.LoadFile();


}
catch(System.IO.FileNotFoundException)
{
MessageBox.Show("No file to load yet");
}
}

[Knight94]

private void openFileDialog_FileOk(object sender, System.ComponentModel.CancelEventArgs e)
{
try
{
this.rtfText.LoadFile(openFileDialog.FileName);//Use file name from open-dialog


}
catch(System.IO.FileNotFoundException)
{
MessageBox.Show("No file to load yet");
}
}

[BinaryTreeEx]

OpenFileDialog cOpenFileDialog = new OpenFileDialog();
cOpenFileDialog.Filter = "wav files (*.wav)|*.wav|mp3 files (*.mp3)|*.mp3";
cOpenFileDialog.FilterIndex = 1;

if (cOpenFileDialog.ShowDialog() == DialogResult.OK)
{
if (cOpenFileDialog.FileName == null || cOpenFileDialog.FileName == "")
{
MessageBox.Show("Please select a file.");
return;
}
if (File.Exists(cOpenFileDialog.FileName) == false)
{
MessageBox.Show("The picture file is not exist.");
return;
}
if (LoadVoiceFile(cOpenFileDialog.FileName) != SYS_RETURN.OK)
MessageBox.Show("Fail to open picture file.");
}