StreamWriter和StreamReader-----文件的读取和写入

使用StreamWriter类可以实现文本文件的写入：
<table border="1">
            <tr>
                <td colspan="2" style="color: #660066;">
                    文本文件的写入：
                </td>
            </tr>
            <tr>
                <td style="font-size: 10pt">
                    请输入文件名：
                </td>
                <td style="width: 158px">
                    <asp:TextBox ID="FileTextBox" runat="server"></asp:TextBox>
                </td>
               
            </tr>
            <tr>
                <td style="width: 158px">
                   请输入文件内容：
                </td>
         
                <td>
                    <asp:TextBox ID="contentTextBox" runat="server" TextMode="MultiLine" Height="216px" Width="216px"></asp:TextBox>
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <asp:Label ID="MsgLabel" runat="server" ></asp:Label>
                </td>
            </tr>
            <tr>
                <td align="center" colspan="2">
                    <asp:Button ID="SureButton" runat="server" Text="确定写入" OnClick="SureButton_Click"/>
                </td>
            </tr>
        </table>
using System.IO;

 protected void SureButton_Click(object sender, EventArgs e)
    {
        try
        {
            if (File.Exists(FileTextBox.Text))
            {
                MsgLabel.Text = "该文件已经存在！";

                return;
            }
            else
            {
                StreamWriter sw = File.CreateText(FileTextBox.Text);
                sw.WriteLine(contentTextBox.Text);
                sw.Close();
                MsgLabel.Text = "写入成功！";
            }
        }
        catch (Exception ee)
        {
            MsgLabel.Text = "写入文件失败！失败原因："+ ee.ToString();
        }
    }


使用StreamReader类可以实现文本文件的读取：
<table border="1">
            <tr>
                <td colspan="2" style="color: #660066;">
                    读取文本文件：
                </td>
            </tr>
            <tr>
                <td style="font-size: 10pt">
                    请输入文件名：
                </td>
                <td style="width: 158px">
                    <asp:TextBox ID="FileTextBox" runat="server"></asp:TextBox>
                </td>
               
            </tr>
            <tr>
                <td align="center" colspan="2">
                    <asp:Button ID="SureButton" runat="server" Text="确定写入" OnClick="SureButton_Click"/>
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <asp:Label ID="MsgLabel" runat="server" ></asp:Label>
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <asp:TextBox ID="contentTextBox" runat="server" TextMode="MultiLine" Height="216px" Width="355px"></asp:TextBox>
                </td>
            </tr>  
        </table>


using System.IO;

  protected void SureButton_Click(object sender, EventArgs e)
    {
        try
        {
            if (!File.Exists(FileTextBox.Text))
            {
                MsgLabel.Text = "该文件不存在！";
                contentTextBox.Visible = false;

                return;
            }
            else
            {
                StreamReader sr = File.OpenText(FileTextBox.Text);
                contentTextBox.Text = sr.ReadToEnd();
                sr.Close();
                contentTextBox.Visible = true;
                MsgLabel.Text = "读取文本文件成功！内容如下：";
            }
        }
        catch (Exception ee)
        {
            MsgLabel.Text = "读取的文本文件处理失败！失败原因："+ee.ToString();
        }
    }