这是什么错误试图从数据库中查看图像

问题描述

任何人都可以帮助这个
正在尝试从数据库查看图像的错误是什么?

路径不能为空.
参数名称:path

这是我的代码....

any one help this
what is this error am trying to view image from Database

Path cannot be null.
Parameter name: path

this is my code....

 protected void btnMulSave_Click(object sender, ImageClickEventArgs e)
        {
            if (txtMulName.Text == "")
            {
                string str1 = "Name field cannot be left blank!!!";
                ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('" + str1 + "');", true);
            }
            else
            {
                if (txtMulName.Text == ddlparent.Text)
                {
                    msgmulliteral.Text = "Municipal Name and its Parent Node cannot be same.";
                }

                else
                {

                    if (fileup.HasFile)
                    {
                        file = fileup.FileName;
                        bool ans = checkFileExtension(file);
                        if (ans)
                        {
                            try
                            {
                                int length = fileup.PostedFile.ContentLength;
                                byte[] imgbyte = new byte[length];
                                HttpPostedFile img = fileup.PostedFile;
                                img.InputStream.Read(imgbyte, 0, length);
                                string imagename = txtMulShortName.Text;
                                SqlConnection connection = new SqlConnection("server=.......;user id=.....;password=....;database=IMADB");
                                connection.Open();
                                SqlCommand cmd = new SqlCommand("INSERT INTO tbllocationdetails (fileup) VALUES (@loclogo)", connection);
                                //cmd.Parameters.Add("@ImageNAme", SqlDbType.VarChar, 50).Value = imagename;
                                cmd.Parameters.Add("@loclogo", SqlDbType.Image).Value = imgbyte;
                                int count = cmd.ExecuteNonQuery();
                                connection.Close();
                            }

                                //fileadd = (Server.MapPath("Image\\") + txtMulShortName.Text + "." + file.Substring(file.LastIndexOf(".") + 1).ToString());
                            //fileup.SaveAs(fileadd);

                            catch (Exception ex) { }
                            locLogo.ImageUrl = "~/Image/" + txtMulName.Text + "." + file.Substring(file.LastIndexOf(".") + 1).ToString();
                        }
                        else
                        {
                            msgmulliteral.Text = "Invalid file type of Logo, select only JPG files";
                        }

                    }
                    if (ddlparent.Text != "None")
                    {
                        DataSet ds = PDataset("select locid from tbllocation where locname='" + ddlparent.Text + "'");
                        foreach (DataRow dr in ds.Tables[0].Rows)
                        {
                            mylocation.parentID = dr["locid"].ToString();
                        }
                    }
                    else
                    {
                        mylocation.parentID = "AA0000";
                    }

                    if (chkMulActive.Checked)
                    {
                        mylocation.active = true;
                    }
                    else
                    {
                        mylocation.active = false;
                    }

                    if (chkMulLogical.Checked)
                    {
                        mylocation.logical = true;
                    }
                    else
                    {
                        mylocation.logical = false;
                    }
                    //Find Previous Entry

                    DataSet d = PDataset("select locpkid, locname from tbllocation where locid='" + txtMunicipalID.Text + "'");
                    DataTable da = d.Tables[0];
                    if (da.Rows.Count > 0)
                    {
                        //Update
                        string str = "UPDATE tbllocation SET "+
                            "locparentid ='" + mylocation.parentID.ToString() + "', " +
                            "locname ='" + txtMulName.Text + "', " +
                            "locactive='" + mylocation.active + "', " + 
                            "userstatus='" + mylocation.logical + "', " + 
                            "locupdate='" + DateTime.Now.ToString() + "', " +
                            "locshortdesc='" + txtMulShortName.Text + "', " +
                            "locdesc='" + txtMulDescription.Text + "' " +
                        "where locpkid='" + da.Rows[0]["locpkid"].ToString() + "'";
                        
                        string updetail = "update tbllocationdetails set locwebsite='" + txtMulWebSite.Text + "', locmanager='" + ddlmanager.Text + "' where locpkid='" + da.Rows[0]["locpkid"].ToString() + "'";

                        
                        SqlConnection conn = new SqlConnection(clsconnection.getConnectionString());
                        SqlCommand cmd = new SqlCommand(str, conn);
                        conn.Open();
                        cmd.ExecuteNonQuery();
                        cmd.CommandText = updetail;
                        cmd.ExecuteNonQuery();
                        conn.Close();
                    }

                    else
                    {
                        //Add New
                        mylocation.ID = txtMunicipalID.Text;
                        mylocation.Name = txtMulName.Text;
                        mylocation.Shorname = txtMulShortName.Text;
                        mylocation.description = txtMulDescription.Text;


                        mylocation.manager = ddlmanager.SelectedValue;
                        mylocation.website = txtMulWebSite.Text;

                        if (fileup.HasFile)
                        {
                            FileStream fs;
                            fs = new FileStream(fileadd, FileMode.Open, FileAccess.Read);
                            byte[] picbyte = new byte[fs.Length];
                            fs.Read(picbyte, 0, System.Convert.ToInt32(fs.Length));
                            fs.Close();
                            mylocation.fileupload = picbyte;
                        }
                        mylocation.locInsert();
                        clearalltextboxes();
                        Addnew();
                        msgmulliteral.Text = "Data Added Successfully";
                        
                    }
                    Response.Redirect("wpaLocationDetails.aspx");
                    rightpanelbtn(false);
                    leftpanelbtn(true);
                }
            }
}

推荐答案

//fileadd = (Server.MapPath("Image\\") + txtMulShortName.Text + "." + file.Substring(file.LastIndexOf(".") + 1).ToString());
                            //fileup.SaveAs(fileadd);

为什么?
您保存文​​件，然后通过
从服务器读取文件

why???
you save file then read file from server by

FileStream fs;
   fs = new FileStream(fileadd, FileMode.Open, FileAccess.Read);

和文件找不到，所以
fs为空
您可以使用

fileup.PostedFile.InputStream作为将其转换为字节的Stream
代替
首先，您将文件保存在服务器上，然后从文件流中读取....

and file not found so
fs is null
you can use

fileup.PostedFile.InputStream as a Stream to convert it to byte
in place of
first you save file on server then read from file stream....

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