如何使用列表框将图像检索到图片框 [英] How to retrieve image to picturebox using listbox

问题描述

我在访问数据库中存储了一些图像。但我无法检索并显示在图片框中。我的代码如下。一切都很好但是。打破数据集。

请更新我在哪里做错了。



private void LoadPicture（）

{

con.Open（）;

cmd.CommandText =从图片中选择图片，其中id ='+ listBox1.Text.ToString（）+' ;

OleDbDataAdapter da = new OleDbDataAdapter（cmd）;

OleDbCommandBuilder cbd = new OleDbCommandBuilder（da）;

DataSet ds = new DataSet（） ;





da.Fill（ds）; //（在这里得到错误）





con.Close（）;

byte [] ap = （byte []）（ds.Tables [0] .Rows [0] [picture]）;

MemoryStream ms = new MemoryStream（ap）;

pictureBox1 .Image = Image.FromStream（ms）;

pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;

pictureBox1.BorderStyle = BorderStyle.Fixed3D;

label1.Text = listBox1.Text.ToString（）;

ms.Close（）;

}

//更新列表框如下。



private void listBox2_SelectedIndexChanged（object sender，EventArgs e）

{

ListBox l =发送者为ListBox ;

if（l.SelectedIndex！= -1）

{

listBox1.SelectedIndex = l.SelectedIndex;

listBox2.SelectedIndex = l.SelectedIndex;

LoadPicture（）;

}

}

I stored some images in access db. But i am not able to retrieve and display in picture box. My code is like below. Everything is good but. Breaking at data set.
Please update me where i am doing wrong.

private void LoadPicture()
{
con.Open();
cmd.CommandText = "select picture from pictures where id ='" + listBox1.Text.ToString() + "'";
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
OleDbCommandBuilder cbd = new OleDbCommandBuilder(da);
DataSet ds = new DataSet();


da.Fill(ds); //(getting Error Here)


con.Close();
byte[] ap = (byte[])(ds.Tables[0].Rows[0]["picture"]);
MemoryStream ms = new MemoryStream(ap);
pictureBox1.Image = Image.FromStream(ms);
pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
pictureBox1.BorderStyle = BorderStyle.Fixed3D;
label1.Text = listBox1.Text.ToString();
ms.Close();
}
//Updated List Box like below.

private void listBox2_SelectedIndexChanged(object sender, EventArgs e)
{
ListBox l = sender as ListBox;
if(l.SelectedIndex != -1)
{
listBox1.SelectedIndex = l.SelectedIndex;
listBox2.SelectedIndex = l.SelectedIndex;
LoadPicture();
}
}

推荐答案

此声明不正确：

This statement is incorrect:

cmd.CommandText = "select picture from pictures where id ='" +
                  listBox1.Text.ToString() +
                  "'";

它应显示为：

It should read:

cmd.CommandText = "select picture from pictures where id ='" +
                  listBox1.SelectedItem.Text +
                  "'";

当然这假设在 listBox1 中选择了一个项目。 此外，你的代码犯了SQL注入罪，但这是一个完全不同的故事。



/ ravi

Of course this assumes an item is selected in listBox1.  Also, your code is guilty of SQL injection, but that's a whole different story.

/ravi

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