图像未保存在数据库中 [英] Image not saving in database

问题描述

void conv_photo()
        {
            //converting photo to binary data
            if (pictureBox3.Image != null)
            {
                ms = new MemoryStream();
                pictureBox3.Image.Save(ms, ImageFormat.Jpeg);
                byte[] photo_aray = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(photo_aray, 0, photo_aray.Length);
                cmd.Parameters.AddWithValue("@photo", photo_aray);
            }
        }

 private void btnsave_Click(object sender, EventArgs e)
        {
            if (comboBox1.SelectedIndex >= 0 && textBox1.Text != "" && textBox2.Text != "" && textBox3.Text != "" && comboBox2.SelectedIndex >= 0 && textBox4.Text != "" && richTextBox1.Text != "")
            {
                try
                {
                    
                    //cmd = new SqlCommand("insert into student_details(class,reg_num,name,father,gender,dob,phone,adrs,img) values('" + comboBox1.Text + "','" + textBox1.Text + "','" + textBox2.Text + "','" + textBox3.Text + "','" + comboBox2.Text + "','" + dateTimePicker1.Text + "','" + textBox4.Text + "','" + richTextBox1.Text + "',@photo)", con);
                    string cmdtext = "insert into student_details(class,reg_num,name,father,gender,dob,phone,adrs,img) values(@class,@reg_num,@name,@father,@gender,@dob,@phone,@adrs,@photo)";
                    SqlCommand cmd = new SqlCommand(cmdtext, con);
                    cmd.Parameters.AddWithValue("@class", comboBox1.Text);
                    cmd.Parameters.AddWithValue("@reg_num", textBox1.Text);
                    cmd.Parameters.AddWithValue("@name", textBox2.Text);
                    cmd.Parameters.AddWithValue("@father", textBox3.Text);
                    cmd.Parameters.AddWithValue("@gender", comboBox2.Text);
                    cmd.Parameters.AddWithValue("@dob", DateTime.Parse(dateTimePicker1.Text));
                    cmd.Parameters.AddWithValue("@phone", textBox4.Text);
                    cmd.Parameters.AddWithValue("@adrs", richTextBox1.Text);
                   
                    conv_photo();
                    con.Open();
                    int n = cmd.ExecuteNonQuery();
                    con.Close();
                    if (n > 0)
                    {
                        MessageBox.Show("record inserted");
                        load();
                        DisplaySummary();
                        student_form_clear();
                        getregnum();
                    }
                
                else
                    MessageBox.Show("insertion failed, please select class and gender");
                
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            }
            else
            {
                MessageBox.Show("Please fill all entries");
            }
            
        }

我尝试过：



我正在尝试此代码，但无法在数据库中保存图像。除了图像，所有数据都可以轻松保存。

错误：必须声明sclare变量@photo

我使用以下数据类型

img = image;

dob =日期;

和其他人的varchar。



哪里有问题请帮帮我

提前感谢

What I have tried:

I am trying this code but unable to save image in database. except image all data saves easily.
ERROR: must declare sclare variable @photo
I used following datatype
img = image;
dob = date;
and varchar for others.

where is problem please help me
thanks in advance

推荐答案

您创建一个新的 SqlCommand 对象名为 cmd 在 btnsave_Click 方法中，作为局部变量。但是，当您再调用 conv_photo 来保存图像时，代码中引用了一个不同的 cmd 对象在代码中的其他地方声明。您应该将 cmd 对象作为参数传递给 conv_photo ，这样您就可以确定它正在寻找正确的对象。

You create a new SqlCommand object named cmd inside your btnsave_Click method, as a local variable. However, when you then call conv_photo to save the image the code there is referring to a different cmd object that has been declared somewhere else in your code. You should pass the cmd object as a parameter to conv_photo so you are sure it is addressing the correct object.

这很简单：你有一个类级别的SqlCommand对象，名为 cmd ，你要将图像作为参数添加到 conv_photo 方法。但是......在你的 btnsave_Click 方法中，你创建了一个同名的新局部变量：

It's pretty simple: you have a class level SqlCommand object called cmd to which you are adding the image as a parameter in your conv_photo method. But...in your btnsave_Click method you create a new local variable of the same name:

SqlCommand cmd = new SqlCommand(cmdtext, con);

你用它来做INSERT操作。

因为他们不喜欢两者都使用相同的SqlCommand实例，@ this参数被添加到错误的SqlCommand并且SQL因此抱怨。

我？我将删除类级别版本，并将相应的SqlCommand对象传递给 conv_photo 方法，以确保始终将其添加到正确的实例。

你的转换不需要那么复杂：

Which you use to do teh INSERT operation.
Because they don't both use the same SqlCommand instance, the @photo parameter is added to the wrong SqlCommand and SQL complains as a result.
Me? I'd delete the class level version, and pass the appropriate SqlCommand object to the conv_photo method to ensure you always add it to the correct instance.
And your conversion doesn't need to be so complex:

MemoryStream ms = new MemoryStream();
imageIn.Save(ms,System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] data = ms.ToArray();

将会这样做。

will do it.

这篇关于图像未保存在数据库中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！