C#实现SMTP邮件附件发送功能详解

这篇文章主要为大家详细介绍了如何利用C#实现SMTP邮件附件发送的功能，文中的示例代码讲解详细，对我们学习C#有一定的帮助，感兴趣的小伙伴可以跟随小编一起了解一下！

实践过程

效果

代码

public partial class frmSend : Form
{
public frmSend()
{
InitializeComponent();
}
//对邮件内容进行编码
private static string Base64Encode(string str)
{
return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
}
private void AddFile(string strFile,MailMessage message)
{
//为要发送的邮件创建附件信息
Attachment myAttachment = new Attachment(strFile, System.Net.Mime.MediaTypeNames.Application.Octet);
//为附件添加时间信息
System.Net.Mime.ContentDisposition disposition = myAttachment.ContentDisposition;
disposition.CreationDate = System.IO.File.GetCreationTime(strFile);
disposition.ModificationDate = System.IO.File.GetLastWriteTime(strFile);
disposition.ReadDate = System.IO.File.GetLastAccessTime(strFile);
message.Attachments.Add(myAttachment);			//将创建的附件添加到邮件中
}
private void SendEmail(MailMessage message)
{
message.Subject = Base64Encode(txtSubject.Text);//设置发送邮件的主题
message.Body = Base64Encode(txtContent.Text);   //设置发送邮件的内容
if (txtAttachment.Text != "")
{
if (txtAttachment.Text.IndexOf(",") != 0)
{
string[] strAttachment = txtAttachment.Text.Split(',');
for (int i = 0; i < strAttachment.Length; i++)
{
AddFile(strAttachment[i], message);
}
}
else
{
AddFile(txtAttachment.Text, message);
}
}
//实例化SmtpClient邮件发送类对象
SmtpClient client = new SmtpClient(txtServer.Text, Convert.ToInt32(txtPort.Text));
//设置用于验证发件人身份的凭据
client.Credentials = new System.Net.NetworkCredential(txtName.Text, txtPwd.Text);
//发送邮件
client.Send(message);
}
private void frmSend_Load(object sender, EventArgs e)
{
txtServer.Text = Dns.GetHostName();
}
private void btnSend_Click(object sender, EventArgs e)
{
try
{
if (validateEmail(txtSend.Text))
{
//设置邮件发送人和接收人
MailMessage message = null;
if (txtTo.Text.IndexOf(",") != -1)
{
string[] strEmail = txtTo.Text.Split(',');
string sumEmail = "";
for (int i = 0; i < strEmail.Length; i++)
{
sumEmail = strEmail[i];
message = new MailMessage(new MailAddress(txtSend.Text), new MailAddress(sumEmail));
SendEmail(message);
}
}
else
{
message = new MailMessage(new MailAddress(txtSend.Text), new MailAddress(txtTo.Text));
SendEmail(message);
}
MessageBox.Show("发送成功");
}
}
catch
{
MessageBox.Show("发送失败!");
}
}
private void btnSelect_Click(object sender, EventArgs e)
{
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
if (txtAttachment.Text == "")
{
txtAttachment.Text = openFileDialog.FileName;
}
else
{
txtAttachment.Text += "," + openFileDialog.FileName;
}
}
}
private void frmSend_FormClosing(object sender, FormClosingEventArgs e)
{
DialogResult = DialogResult.OK;
}
#region  验证输入为Email
/// <summary>
/// 验证输入为Email
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static bool validateEmail(string str)
{
return Regex.IsMatch(str, @"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*");
}
#endregion
}

partial class frmSend
{
/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// 清理所有正在使用的资源。
/// </summary>
/// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows 窗体设计器生成的代码
/// <summary>
/// 设计器支持所需的方法 - 不要
/// 使用代码编辑器修改此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.txtContent = new System.Windows.Forms.TextBox();
this.txtSubject = new System.Windows.Forms.TextBox();
this.txtPort = new System.Windows.Forms.TextBox();
this.txtServer = new System.Windows.Forms.TextBox();
this.txtPwd = new System.Windows.Forms.TextBox();
this.txtName = new System.Windows.Forms.TextBox();
this.txtTo = new System.Windows.Forms.TextBox();
this.txtSend = new System.Windows.Forms.TextBox();
this.label8 = new System.Windows.Forms.Label();
this.label7 = new System.Windows.Forms.Label();
this.label6 = new System.Windows.Forms.Label();
this.label5 = new System.Windows.Forms.Label();
this.label4 = new System.Windows.Forms.Label();
this.label3 = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
this.label1 = new System.Windows.Forms.Label();
this.btnSend = new System.Windows.Forms.Button();
this.txtAttachment = new System.Windows.Forms.TextBox();
this.label9 = new System.Windows.Forms.Label();
this.btnSelect = new System.Windows.Forms.Button();
this.openFileDialog = new System.Windows.Forms.OpenFileDialog();
this.SuspendLayout();
// 
// txtContent
// 
this.txtContent.Location = new System.Drawing.Point(23, 143);
this.txtContent.Multiline = true;
this.txtContent.Name = "txtContent";
this.txtContent.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
this.txtContent.Size = new System.Drawing.Size(519, 100);
this.txtContent.TabIndex = 7;
// 
// txtSubject
// 
this.txtSubject.Location = new System.Drawing.Point(88, 94);
this.txtSubject.Name = "txtSubject";
this.txtSubject.Size = new System.Drawing.Size(186, 21);
this.txtSubject.TabIndex = 6;
// 
// txtPort
// 
this.txtPort.Location = new System.Drawing.Point(356, 62);
this.txtPort.Name = "txtPort";
this.txtPort.Size = new System.Drawing.Size(186, 21);
this.txtPort.TabIndex = 5;
// 
// txtServer
// 
this.txtServer.Location = new System.Drawing.Point(88, 63);
this.txtServer.Name = "txtServer";
this.txtServer.Size = new System.Drawing.Size(186, 21);
this.txtServer.TabIndex = 4;
// 
// txtPwd
// 
this.txtPwd.Location = new System.Drawing.Point(356, 34);
this.txtPwd.Name = "txtPwd";
this.txtPwd.PasswordChar = '*';
this.txtPwd.Size = new System.Drawing.Size(186, 21);
this.txtPwd.TabIndex = 3;
// 
// txtName
// 
this.txtName.Location = new System.Drawing.Point(88, 35);
this.txtName.Name = "txtName";
this.txtName.Size = new System.Drawing.Size(186, 21);
this.txtName.TabIndex = 2;
// 
// txtTo
// 
this.txtTo.Location = new System.Drawing.Point(356, 6);
this.txtTo.Name = "txtTo";
this.txtTo.Size = new System.Drawing.Size(186, 21);
this.txtTo.TabIndex = 1;
// 
// txtSend
// 
this.txtSend.Location = new System.Drawing.Point(88, 6);
this.txtSend.Name = "txtSend";
this.txtSend.Size = new System.Drawing.Size(186, 21);
this.txtSend.TabIndex = 0;
// 
// label8
// 
this.label8.AutoSize = true;
this.label8.Location = new System.Drawing.Point(15, 121);
this.label8.Name = "label8";
this.label8.Size = new System.Drawing.Size(65, 12);
this.label8.TabIndex = 12;
this.label8.Text = "邮件内容：";
// 
// label7
// 
this.label7.AutoSize = true;
this.label7.Location = new System.Drawing.Point(15, 93);
this.label7.Name = "label7";
this.label7.Size = new System.Drawing.Size(65, 12);
this.label7.TabIndex = 11;
this.label7.Text = "邮件主题：";
// 
// label6
// 
this.label6.AutoSize = true;
this.label6.Location = new System.Drawing.Point(290, 65);
this.label6.Name = "label6";
this.label6.Size = new System.Drawing.Size(53, 12);
this.label6.TabIndex = 14;
this.label6.Text = "端口号：";
// 
// label5
// 
this.label5.AutoSize = true;
this.label5.Location = new System.Drawing.Point(21, 65);
this.label5.Name = "label5";
this.label5.Size = new System.Drawing.Size(53, 12);
this.label5.TabIndex = 17;
this.label5.Text = "服务器：";
// 
// label4
// 
this.label4.AutoSize = true;
this.label4.Location = new System.Drawing.Point(278, 37);
this.label4.Name = "label4";
this.label4.Size = new System.Drawing.Size(77, 12);
this.label4.TabIndex = 16;
this.label4.Text = "发件人密码：";
// 
// label3
// 
this.label3.AutoSize = true;
this.label3.Location = new System.Drawing.Point(9, 37);
this.label3.Name = "label3";
this.label3.Size = new System.Drawing.Size(77, 12);
this.label3.TabIndex = 15;
this.label3.Text = "发件人名称：";
// 
// label2
// 
this.label2.AutoSize = true;
this.label2.Location = new System.Drawing.Point(290, 9);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(53, 12);
this.label2.TabIndex = 13;
this.label2.Text = "收件人：";
// 
// label1
// 
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(21, 9);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(53, 12);
this.label1.TabIndex = 18;
this.label1.Text = "发件人：";
// 
// btnSend
// 
this.btnSend.Location = new System.Drawing.Point(221, 280);
this.btnSend.Name = "btnSend";
this.btnSend.Size = new System.Drawing.Size(116, 23);
this.btnSend.TabIndex = 9;
this.btnSend.Text = "发送";
this.btnSend.UseVisualStyleBackColor = true;
this.btnSend.Click += new System.EventHandler(this.btnSend_Click);
// 
// txtAttachment
// 
this.txtAttachment.Location = new System.Drawing.Point(62, 250);
this.txtAttachment.Name = "txtAttachment";
this.txtAttachment.Size = new System.Drawing.Size(437, 21);
this.txtAttachment.TabIndex = 28;
// 
// label9
// 
this.label9.AutoSize = true;
this.label9.Location = new System.Drawing.Point(15, 253);
this.label9.Name = "label9";
this.label9.Size = new System.Drawing.Size(41, 12);
this.label9.TabIndex = 27;
this.label9.Text = "附件：";
// 
// btnSelect
// 
this.btnSelect.Location = new System.Drawing.Point(505, 249);
this.btnSelect.Name = "btnSelect";
this.btnSelect.Size = new System.Drawing.Size(37, 23);
this.btnSelect.TabIndex = 8;
this.btnSelect.Text = "选择";
this.btnSelect.UseVisualStyleBackColor = true;
this.btnSelect.Click += new System.EventHandler(this.btnSelect_Click);
// 
// openFileDialog
// 
this.openFileDialog.FileName = "openFileDialog1";
// 
// frmSend
// 
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(551, 313);
this.Controls.Add(this.btnSelect);
this.Controls.Add(this.txtAttachment);
this.Controls.Add(this.label9);
this.Controls.Add(this.txtContent);
this.Controls.Add(this.txtSubject);
this.Controls.Add(this.txtPort);
this.Controls.Add(this.txtServer);
this.Controls.Add(this.txtPwd);
this.Controls.Add(this.txtName);
this.Controls.Add(this.txtTo);
this.Controls.Add(this.txtSend);
this.Controls.Add(this.label8);
this.Controls.Add(this.label7);
this.Controls.Add(this.label6);
this.Controls.Add(this.label5);
this.Controls.Add(this.label4);
this.Controls.Add(this.label3);
this.Controls.Add(this.label2);
this.Controls.Add(this.label1);
this.Controls.Add(this.btnSend);
this.Name = "frmSend";
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
this.Text = "使用SMTP服务发送带附件的邮件";
this.Load += new System.EventHandler(this.frmSend_Load);
this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.frmSend_FormClosing);
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.TextBox txtContent;
private System.Windows.Forms.TextBox txtSubject;
private System.Windows.Forms.TextBox txtPort;
private System.Windows.Forms.TextBox txtServer;
private System.Windows.Forms.TextBox txtPwd;
private System.Windows.Forms.TextBox txtName;
private System.Windows.Forms.TextBox txtTo;
private System.Windows.Forms.TextBox txtSend;
private System.Windows.Forms.Label label8;
private System.Windows.Forms.Label label7;
private System.Windows.Forms.Label label6;
private System.Windows.Forms.Label label5;
private System.Windows.Forms.Label label4;
private System.Windows.Forms.Label label3;
private System.Windows.Forms.Label label2;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Button btnSend;
private System.Windows.Forms.TextBox txtAttachment;
private System.Windows.Forms.Label label9;
private System.Windows.Forms.Button btnSelect;
private System.Windows.Forms.OpenFileDialog openFileDialog;
}

文档下载：C#实现SMTP邮件附件发送功能详解.doc文档