从SQL BASE C＃中选择IMAGE [英] Select IMAGE from SQL BASE C#
本文介绍了从SQL BASE C＃中选择IMAGE的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
此代码正常工作。
sql中图像的列名是数据。
In这段代码我需要把图片格式数据库放到图片盒里
一些帮助
什么我试过了：
This code working fine.
Column name for image in sql is data.
In this code I need to put inside picture form database to picturebox
Some help
What I have tried:
private void prijavaAction() //04.04. final doradjena perfect
{
{
SqlConnection con = new SqlConnection(cs);
if (textBox1.Text.All(char.IsDigit))
{
string queryString = "SELECT [ime_prezime] FROM dbo.radnici WHERE bar_kod = '" + textBox1.Text + "'";// pronaci radnika u bazi
using (SqlConnection connection = new SqlConnection(cs))
{
SqlCommand command = new SqlCommand(queryString, connection);
connection.Open();
SqlDataReader reader = command.ExecuteReader();
string commanda = "select case when (SELECT (DATEDIFF(SECOND, Max(vrijemeprijave), GETDATE()) / 60) from dbo.prijava_radnika where status='prijavljen' and radnik= (" + queryString + ")) < 5 THEN 1 ELSE 0 END";
SqlConnection connection3 = new SqlConnection(cs);
SqlCommand command2 = new SqlCommand(commanda, connection3);
connection3.Open();
int broj = Convert.ToInt32(command2.ExecuteScalar());
string commanda2 = "select case when (SELECT (DATEDIFF(SECOND, Max(vrijemeodjave), GETDATE()) / 60) from dbo.prijava_radnika where status='odjavljen' and radnik= (" + queryString + ")) < 5 THEN 1 ELSE 0 END";
SqlConnection connection4 = new SqlConnection(cs);
SqlCommand command4 = new SqlCommand(commanda2, connection4);
connection4.Open();
int broj2 = Convert.ToInt32(command4.ExecuteScalar());
if (broj == 1 || broj2 == 1)
{
notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml("#FD7400");
messageLabel.Text = "Prijava i odjava su blokirani 5 minuta \nza ovog radnika";
textBox1.Text = "";
}
else
{
try
{
if (reader.Read())
{
string prijava = "SELECT count(*) from dbo.prijava_radnika where vrijemeprijave is not null and vrijemeodjave is null and radnik = '" + readerresultTextbox.Text + "' and redni_broj is NULL";
SqlCommand provjeraprijaveradnika = new SqlCommand(prijava, con);
con.Open();
int result = Convert.ToInt32(provjeraprijaveradnika.ExecuteScalar());
con.Close();
if ((result == 0))
{
String saveStaff = "INSERT INTO dbo.prijava_radnika (vrijemeprijave, status, radnik,idfakture) VALUES(@vrijemeprijave,'prijavljen', '" + readerresultTextbox.Text + "',@idfakture)";
using (SqlConnection openCon2 = new SqlConnection(cs))
{
using (SqlCommand querySaveStaff = new SqlCommand(saveStaff))
{
querySaveStaff.Connection = openCon2;
querySaveStaff.Parameters.Add("@vrijemeprijave", SqlDbType.DateTime).Value = DateTime.Now;
querySaveStaff.Parameters.Add("@idfakture", SqlDbType.Int).Value = id_fakture;
openCon2.Open();
querySaveStaff.ExecuteNonQuery();
openCon2.Close();
notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml("#2EFF36");
// messageLabel.Text = (reader["ime_prezime"].ToString()) + " je prijavljen u \n " + DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss");
messageLabel.Text = ("Dobro došli na posao...\n" + reader["ime_prezime"].ToString()) + " \nPrijavljeni ste od\n " + DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss");
readerresultTextbox.Text = (reader["ime_prezime"].ToString());
}
}
}
else
{
String updateStaff = " declare @maxNo integer = 0 select @maxNo = isnull(max(redni_broj), 0) from[dbo].[prijava_radnika] UPDATE[dbo].[prijava_radnika] SET"
+ " [vrijemeodjave] = @vrijemeodjave,[redni_broj] = (@maxNo+1),[status] = 'odjavljen' WHERE radnik = '" + readerresultTextbox.Text + "'and [status] = 'prijavljen'";
using (SqlConnection connection1 = new SqlConnection(cs))
{
SqlCommand command1 = new SqlCommand(queryString, connection1);
connection1.Open();
SqlDataReader reader1 = command1.ExecuteReader();
connection.Close();
try
{
if (reader1.Read())
{
using (SqlConnection openCon3 = new SqlConnection(cs))
{
using (SqlCommand queryupdateStaff = new SqlCommand(updateStaff))
{
queryupdateStaff.Connection = openCon3;
queryupdateStaff.Parameters.Add("@vrijemeodjave", SqlDbType.DateTime).Value = DateTime.Now;
openCon3.Open();
queryupdateStaff.ExecuteNonQuery();
openCon3.Close();
}
}
notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml("#FFE11A");
messageLabel.Text = (reader1["ime_prezime"].ToString()) + " je odjavljen u \n " + DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss");
}
}
catch { }
}
reader.Close();
}
}
else
{
notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml("#FD7400");
messageLabel.Text = "Radnik ne postoji u bazi! \nProverite vašu karticu ili probajte ponovo!";
textBox1.Text = "";
}
}
finally
{
}
}
}
}
else
{
notificationPanel.BackColor = System.Drawing.ColorTranslator.FromHtml("#FD7400");
messageLabel.Text = "Bar kod nije važeci ili nije bar kod";
textBox1.Text = "";
}
}
}
推荐答案
您必须查看调试器，但通常图像数据的数据类型是byte []。所以，你的问题是从byte []转换为Image。如果是这样，下面的内容应该可以解决问题：
You'll have to look in the debugger, but generally the data type for image data isbyte[]. So, you're problem is to convert frombyte[]toImage. If so, something like the following should do the trick:
using (var stream = new MemoryStream((byte[])reader4["data"]))
pictureBox.Image = Image.FromStream(stream);
祝你好运，希望有所帮助。
Good luck, hope that helps.
已经指出你需要以二进制格式处理数据。有关完整示例，请查看 c＃ - 从sql server数据库中检索图像 - DeveloperQ - 开发者问题网 - 海量问题解决方案 [ ^ ]
其他问题
- 您应该在查询中使用参数。正如所指出的那样，当将字符串连接到SQL语句时，你最终会遇到问题
- 空的catch块，如果发生错误，则省略所有异常，因为你有一个空的catch块。您至少应该向用户显示一条消息，告知执行不成功
- 多个连接。看起来你在执行过程中打开了多个连接，为什么？这只会增加不必要的代码并减慢程序的速度
As already pointed out you need to handle the data in binary format. For a complete example, have a look at c# - Retrieve Images from sql server database - Stack Overflow[^]
Other issues
- You should use parameters with your queries. As pointed out you're going to end up with problems when just concatenating strings into the SQL statement
- Empty catch block, if an error occurs you omit all exceptions because you have an empty catch block. You should at least show a message to the user to inform about unsuccessful execution
- Multiple connections. It looks like you're opening multiple connections during the execution, why? This only adds unnecessary code and slows down the program
最后我添加但是我有错误
On finally I add but I have error
Error CS0029 Cannot implicitly convert type 'string' to 'System.Drawing.Image'
string slika = "SELECT [data] FROM dbo.radnici WHERE ime_prezime = '" + readerresultTextbox.Text + "'";// pronaci radnika u bazi
using (SqlConnection connection2 = new SqlConnection(cs))
{
SqlCommand command3 = new SqlCommand(slika, connection2);
connection2.Open();
SqlDataReader reader4 = command3.ExecuteReader();
connection2.Close();
if(reader4.Read())
{
pictureBox.Image = (reader4["data"].ToString());
}
else
{
//
}
}
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