protected void BtnOk_Click(object sender, EventArgs e)

    {

        if (this.FileUpload1.FileName == "")

        {

            this.lblMessage.Text = "<font color=#FF0000>请选择上传的图片!</font>";

            this.FileUpload1.Focus();

            return;

        }

        string filePath = this.FileUpload1.FileName;

string fileName = filePath.Substring(filePath.LastIndexOf("\\")+1);

        string fileType = filePath.Substring(filePath.LastIndexOf(".")+1);

        string filePic = Server.MapPath("~/images/" + fileName);

        string[] strArr = new string[] { "gif", "jpg", "bmp" };

        for (int i = 0; i < strArr.Length; i++)

        {

            if (fileType.ToLower() == strArr[i])

            {

                this.FileUpload1.PostedFile.SaveAs(filePic);

                this.lblMessage.Text = "上传图片成功!";

                return;

            }

        }

        this.lblMessage.Text = "您上传的图片格式不正确\n,请上传jpg,gif,bmp格式的图片.";

    }