savefiledialog用法_空白文档的默认文件名

private void btnSelectXml_Click(object sender, EventArgs e)
        {
            OpenFileDialog XmlPath = new OpenFileDialog();
            XmlPath.Title = "选择文件A";
            XmlPath.Filter = "xml文件(*.xml)|*.xml";//过滤文件类型只能为xml
            XmlPath.RestoreDirectory = false;//每次打开位置与上一次相同

            if (XmlPath.ShowDialog() == DialogResult.OK)
            {
                txtXmlPath.Text = System.IO.Path.GetFullPath(XmlPath.FileName);
            }
        }

private void btnSelectSavePathExcel_Click(object sender, EventArgs e)
        {
            SaveFileDialog savePath = new SaveFileDialog();
            savePath.Title = "保存文件";
            savePath.Filter = "xlsx文件(*.xlsx)|*.xlsx";
            savePath.RestoreDirectory = false;
            savePath.FileName = getFilename(txtXmlPath.Text);

            if (savePath.ShowDialog() == DialogResult.OK)
            {
                txtSavePathExcel.Text = savePath.FileName;
            }
        }

public string getFilename(string sxmlpath)
        {
            string str = "";
            int a= sxmlpath.LastIndexOf('\\');
            int b = sxmlpath.LastIndexOf('.');
            str = sxmlpath.Substring(a + 1, b - a - 1);
            return str;
        }