winform 保存文件 打开文件 选择文件 字体样式颜色（流 using System.IO;）

string filePath = "";

        private void 保存SToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (filePath.Length <= 0)
            {
                saveFileDialog1.Filter = "文本文件|*.txt";
                saveFileDialog1.FileName = "新建文本文件";
                DialogResult dr = saveFileDialog1.ShowDialog();

                if (dr == DialogResult.OK)
                {
                    string path = saveFileDialog1.FileName;
                    StreamWriter sw = new StreamWriter(path);
                    sw.Write(textBox1.Text);
                    sw.Flush();
                    filePath = path;
                }
            }
            else
            {
                StreamWriter sw = new StreamWriter(filePath);
                sw.Write(textBox1.Text);
                sw.Flush();
            }

        }

保存文件 

private void 打开OToolStripMenuItem_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter = "文本文件|*.txt|C#代码文件|*.cs|全部文件|*.*";
            DialogResult dr = openFileDialog1.ShowDialog();
            if (dr == DialogResult.OK)
            {
                string path = openFileDialog1.FileName;


                StreamReader sr = new StreamReader(path, Encoding.Default);
                textBox1.Text = sr.ReadToEnd();

                string[] name = openFileDialog1.FileName.Split('\\');

                this.Text = name[name.Length - 1] + " - 记事本";

            }
        }

打开文件

private void 选择文件夹ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            DialogResult dr = folderBrowserDialog1.ShowDialog();
            if (dr == DialogResult.OK)
            {
                textBox1.Text = folderBrowserDialog1.SelectedPath;

            }
        }

选择文件

private void 字体ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            DialogResult dr = fontDialog1.ShowDialog();

            if (dr == DialogResult.OK)
            {
                textBox1.Font = fontDialog1.Font;
                textBox1.ForeColor = fontDialog1.Color;


            }
        }

字体样式  颜色

 using System.IO;