C#读取文件

private void button2_Click(object sender, EventArgs e)
{
    string file = "";
    OpenFileDialog openFileDialog = new OpenFileDialog();
    openFileDialog.InitialDirectory = "c:\";//注意这里写路径时要用c:\而不是c:
    openFileDialog.Filter = "Html|*.html|Mht|*.mht|htm|*.htm";
    openFileDialog.RestoreDirectory = true;
    openFileDialog.FilterIndex = 1;
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        file = openFileDialog.FileName;

        //string fileContent = File.ReadAllText(file, Encoding.Default);//第一种方式

        //第二种方式
        string strLine = "";
        using (System.IO.StreamReader sr = new System.IO.StreamReader(file,Encoding.Default))
        {                   
            strLine = sr.ReadToEnd();
        }
        //System.Console.WriteLine(strLine);
        this.textBox1.Text = strLine;
    }

}

读出来的有可能出出现乱码，这个主要是跟编码格式有关，可以尝试去设置Encoding的属性去修改编码格式。