how to send fields (Database Access) in Arrey

Question

hi ...
my Database (Access) have 3 fields (Pic, Sub, Date) ---> Pic type : OLE object
how to send fields (Database Access) in Arrey ...
then with button (Next / Perview) show Pic in a pictureBox and label ?
my project is PicGallery :)

Vulpes · Answer

OK, I've altered it to fit in with your existing declarations: public static string Albumstring = string.Format(@"Provider = Microsoft.Jet.OLEDB.4.0;Data Source = {0}\Data.mdb", Application.StartupPath.ToString()); OleDbConnection con = new OleDbConnection(Albumstring); OleDbCommand com = null ; private int index = 0; private List picList; private void Form2_Load(object sender, EventArgs e) { picList = new List (); string cmdString = "SELECT Pic, Sub, Alb FROM Aks"; con.Open(); com = new OleDbCommand(cmdString, con); var reader = com .ExecuteReader(); while (reader.Read()) { byte[] bytes = (byte[])reader["Pic"]; var ms = new System.IO.MemoryStream(bytes); Image pic = Image.FromStream(ms); string sub = reader["Sub"].ToString(); string alb = reader["Alb"].ToString(); var picData = new PicData(pic, sub, alb); picList.Add(picData); } reader.Close(); con.Close(); button2.PerformClick(); }

Vulpes · Answer

I can't find anything wrong with the code but you don't appear to be actually displaying the image found or the first such image. Try making the highlighted changes: private void textBox1_Leave(object sender, EventArgs e) { picList = new List (); if (textBox1.Text.Trim() == "") return; string Albumstring = "SELECT Pic, Sub, Alb, Date FROM Pic WHERE Alb='" + textBox1.Text + "'"; com.Parameters.Clear(); // com.Parameters.AddWithValue("a", textBox1.Text.Trim()); con.Open(); com = new OleDbCommand(Albumstring, con); var reader = com.ExecuteReader(); while (reader.Read()) { byte[] bytes = (byte[])reader["Pic"]; var ms = new System.IO.MemoryStream(bytes); Image pic = Image.FromStream(ms); string alb = reader["Alb"].ToString(); string sub = reader["Sub"].ToString(); string dat = reader["Date"].ToString(); var picData = new PicData(pic, sub, alb, dat); picList.Add(picData); } reader.Close(); con.Close(); index = 0; if (picList.Count > 0) { Next_Click(null, null); } else { pictureBox1.Image = null; } }

Vulpes · Answer

I've noticed now that you've got the code for this in the textBox1_TextChanged handler so it will be executed each time the user types (or deletes) a character or the Text property is set programatically! Worse still, as 'com' is defined at class level, a new parameter will be added each time the TextChanged event is fired. Ideally, this code should be in a button_Click handler but you could also put it in textBox1's Leave handler so that it won't be executed until the user has finished typing and moved the input focus to a new control. I'd also make some changes: 1. Insert this line at the beginning so the code won't execute if the textbox is blank: if(textBox1.Text.Trim() == "") return; 2. Just before this line: com.parameters.AddWithValue("a", textBox1.Text); clear out any previous parameters by inserting this line: com.Parameters.Clear(); 3. Make sure there's no superfluous whitespace by replacing this line: com.Parameters.AddWithValue("a", textBox1.Text); with this one: com.Parameters.AddWithValue("a", textBox1.Text.Trim()); 4. If you still get an error, then forget about parameters (at least for the time being) and replace these lines: string cmdString = "SELECT Pic, Sub, Alb FROM Aks WHERE Alb=?"; com.Parameters.Clear(); com.Parameters.AddWithValue("a", textBox1.Text.Trim()); with this one: string cmdString = "SELECT Pic, Sub, Alb FROM Aks WHERE Alb='" + textBox1.Text + "'";

Vulpes · Answer

Sorry, it should be an upper case 'P': com. Parameters. AddWithValue("a", textBox1.Text);

Vulpes · Answer

Ah, it's just dawned on me that you're using MS Access here which (unlike SQL Server) doesn't use @ as the parameter prefix in the query itself. It uses ? instead but identifies parameters by their positions in the parameter collection rather than their names. Try this instead: string cmdString = "SELECT Pic, Sub, Alb FROM Aks WHERE Alb=?"; com.parameters.AddWithValue("a", textBox1.Text);

Vulpes · Answer

Well, this is quite a common pattern when you need to display successive elements of a collection in Windows Forms programming and so I suppose you could try and remember what to do if it crops up again. However, personally, I never try to remember stuff such as this. I just work out the logic from first principles each time it's needed. That way I can deal with any variations that might occur as you usually find that no two situations in computing are exactly the same.

Vulpes · Answer

If you'd like it to work in a similar way to the Next button, except in the reverse direction, then try this: private void Perview_Click(object sender, EventArgs e) { index--; if (index pictureBox1.Image = picList[index].Pic; label2.Text = picList[index].Sub; label1.Text = picList[index].Alb; label3.Text = picList[index].Date; }

Vulpes · Answer

If you want to move backwards, rather than back to the beginning, when the end of the list is reached, then I'd use this code: // declare additonal field bool moveBack = false; private void btnNext_Click(object sender, EventArgs e) { pictureBox1.Image = picList[index].Pic; label1.Text = picList[index].Sub; label2.Text = picList[index].Alb; if (!moveBack) { index++; if (index >= picList.Count) { moveBack = true; index = picList.Count - 2; if (index } } else { index--; if (index { moveBack = false; index = 1; if (index >= picList.Count) index = 0; } } }

Vulpes · Answer

This line: var picList = new List (); should be: picList = new List (); // now assigning to field The warning should now go away.

Vulpes · Answer

Not doing very well here, am I? The 'i' should be 'index': pictureBox1.Image = picList[ index ].Pic; lblSub.Text = picList[ index ].Sub; lblDate.Text = picList[ index ].Date.ToShortDateString(); index++; if (index >= picList.Count) index = 0;

Vulpes · Answer

Sorry, it should be: private List picList; I'm writing this stuff off the top of my head and so mistakes, unfortunately, are inevitable.

Vulpes · Answer

Add this using directive at the top of the class file as it doesn't look like it's added by default: using System.Drawing;

Vulpes · Answer

I'd create a separate class to hold the image data: class PicData { public Image Pic {get; set;} public string Sub {get; set;} public DateTime Date {get; set;} public PicData(Image pic, string sub, DateTime date) { Pic = pic; Sub = sub; Date = date; } } If the image is now a BLOB rather than an Ole Object in the Access database, the code in your form class will be along the following lines: private int index = 0; private List PicData > picList; // EDITED private void Form1_Load(object sender, EventArgs e) { var picList = new List (); string conString = "whatever"; var con = new OleDbConnection(conString); string cmdString = "SELECT pic, sub, date FROM sometable"; con.Open(); var cmd = new OleDbCommand(cmdString, con); var reader = cmd.ExecuteReader(); while(reader.Read()) { byte[] bytes = (byte[])reader["pic"]; var ms = new System.IO.MemoryStream(bytes); Image pic = Image.FromStream(ms); string sub = reader["sub"].ToString(); DateTime date = Convert.ToDateTime(reader["date"].ToString()); var picData = new PicData(pic, sub, date); picList.Add(picData); } reader.Close(); con.Close(); btnNext.PerformClick(); // load first image } private void btnNext_Click ( object sender, EventArgs e) // EDITED { pictureBox1.Image = picList[ index] .Pic; // EDITED lblSub.Text = picList[ index ].Sub; // EDITED lblDate.Text = picList[ index ].Date.ToShortDateString(); // EDITED index++; if (index >= picList.Count) index = 0; }

Sumit Jolly · Answer

generally PICs are stored into BLOB and other similar data types because they store it as binary. I think if you've OLE object then you need to first convert into binary and then store into BLOB datatype.

ghasem deh · Answer

thank you ... MessageBox Error Again ---- Forget this ! ---- thanks

ghasem deh · Answer

not happen !

Vulpes · Answer

You still have the code in textBox1_TextChanged. Try putting it in textBox1_Leave instead.

ghasem deh · Answer

excuse me for get your time this code NO error ... But not happen ! private void textBox1_TextChanged(object sender, EventArgs e) { picList = new List (); if (textBox1.Text.Trim() == "") return; string Albumstring = "SELECT Pic, Sub, Alb, Date FROM Pic WHERE Alb='" + textBox1.Text + "'"; com.Parameters.Clear(); // com.Parameters.AddWithValue("a", textBox1.Text.Trim()); con.Open(); com = new OleDbCommand(Albumstring, con); var reader = com.ExecuteReader(); while (reader.Read()) { byte[] bytes = (byte[])reader["Pic"]; var ms = new System.IO.MemoryStream(bytes); Image pic = Image.FromStream(ms); string alb = reader["Alb"].ToString(); string sub = reader["Sub"].ToString(); string dat = reader["Date"].ToString(); var picData = new PicData(pic, sub, alb, dat); picList.Add(picData); } reader.Close(); con.Close();

ghasem deh · Answer

post 25 (iamge) --- massegBox Error !

Vulpes · Answer

What's the error this time?

ghasem deh · Answer

thanks for answer show massageBox ERROR again ...

ghasem deh · Answer

now this ERROR ...

ghasem deh · Answer

hi ... this ERROR

Vulpes · Answer

The query looks OK. What error are you getting?

ghasem deh · Answer

How to search by album ? i use this code : string cmdString = "SELECT Pic, Sub, Alb FROM Aks WHERE Alb=@a"; com.parameters.AddWithValue("@a", textBox1.Text); but --> ERROR ! i want display pic Based on Album name ...

ghasem deh · Answer

thank you very much ... :) how to me learn it ?

ghasem deh · Answer

this code : private void Next_Click(object sender, EventArgs e) { pictureBox1.Image = picList[index].Pic; label2.Text = picList[index].Sub; label1.Text = picList[index].Alb; label3.Text = picList[index].Date; index++; if (index >= picList.Count) index = 0; } private void Perview_Click(object sender, EventArgs e) { try { if (index { index--; pictureBox1.Image = picList[index].Pic; label2.Text = picList[index].Sub; label1.Text = picList[index].Alb; label3.Text = picList[index].Date; if (index == 0) Perview.Enabled = false; } } catch { MessageBox.Show("????? ?? ???? ? ???? ????? ???? ??????","Error",MessageBoxButtons.OK,MessageBoxIcon.Error); } }

Vulpes · Answer

Can you post the code you currently have for the preview button please.

ghasem deh · Answer

hi ... Vulpes you are here ? this project (TEST) ... Next key OK but Perview key when click on (last image in array) error ! if 10 image in database , Perview from image 9 ... ok BUT from image 10 send erro !

ghasem deh · Answer

you are best ... i write this code to Perview Key : pictureBox1.Image = picList[index].Pic; label1.Text = picList[index].Sub; label2.Text = picList[index].Alb; index--; if (index But only a picture to go back ... error

ghasem deh · Answer

error again ... this my project I'm confused ... please checked !

ghasem deh · Answer

this my connection : public static string Albumstring = string.Format(@"Provider = Microsoft.Jet.OLEDB.4.0;Data Source = {0}\Data.mdb", Application.StartupPath.ToString()); OleDbConnection con = new OleDbConnection(Albumstring); OleDbCommand com = new OleDbCommand(); and change (Date) to (Alb = Text) ... Error Pic and : private List picList; ==> Warning 1 Field 'Scanner_Test.Form2.picList' is never assigned to, and will always have its default value null

ghasem deh · Answer

Thank you for attention and Answers ... ---------------------------------------- int i; pictureBox1.Image = picList[ i ].Pic; lblSub.Text = picList[i].Sub; lblDate.Text = picList[i].Date.ToShortDateString(); index++; if (index >= picList.Count) index = 0; Error : Error 1 Use of unassigned local variable 'i'

ghasem deh · Answer

excuse me ! private List picData > picList; Error : Error 1 The type or namespace name 'picData' could not be found (are you missing a using directive or an assembly reference?)

ghasem deh · Answer

public Image Pic {get; set;} public string Sub {get; set;} public DateTime Date {get; set;} public PicData( Image pic, string sub, DateTime date) { Pic = pic; Sub = sub; Date = date; } Error : Error 1 The type or namespace name 'Image' could not be found (are you missing a using directive or an assembly reference?)

ghasem deh · Answer

with bitMap method convert to binary and insert into table . now , i want read from table (with arrey) and show in form ...

how to send fields (Database Access) in Arrey

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Answers (36)