检索图片框中的图像 [英] retrieve images in picture box

问题描述

当我通过带有Image列的dgv时，我有一个小的isssure，我需要在dgv旁边的图片框中更改图像



我在form_load上有这个代码和dgID_textchanged

I have a small isssure when I am going thru dgv with Image column and I need to change images in picture box beside dgv

I have this code on form_load and dgID_textchanged

if (image1.Image != null)
    image1.Image.Dispose();


SqlCommand cmd22 = new SqlCommand("Image_proc", cs);
cmd22.CommandType = CommandType.StoredProcedure;
cmd22.Parameters.Add("@imgId", SqlDbType.Int).Value =
          Convert.ToInt32(dgID.Text);
SqlDataAdapter adp = new SqlDataAdapter(cmd22);
DataTable dt = new DataTable();

try
{
    if (cs.State == ConnectionState.Closed)
        cs.Open();
    adp.Fill(dt);
    if (dt.Rows.Count > 0)
    {


        MemoryStream ms = new MemoryStream((byte[])dt.Rows[0]["Image"]);

        image1.Image = Bitmap.FromStream(ms);

        image1.Refresh();
    }

}
catch (Exception ex)
{
    MessageBox.Show(ex.Message, "Error",
          MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
    if (cs.State == ConnectionState.Open)
        cs.Close();
}

当dgv的单元格中有图像时它一切都很好但是它是null值然后我得到错误无法将类型'System.DBNull'的对象强制转换为'System.Byte ...而且我被卡住了



代码块添加 - OriginalGriff [/ edit]

it all works great when there is a image in the cell of dgv but whene it is null value then I get Error Unable to cast object of type 'System.DBNull' to type 'System.Byte ... and I am stuck

[edit]Code block added - OriginalGriff[/edit]

推荐答案

简单 - 检查它。

Simple - check it.

if (dt.Rows.Count > 0)
    {
    object o = dt.Rows[0]["Image"];
    Image im = null;
    if (o != DBNull.Value)
        {
        MemoryStream ms = new MemoryStream((byte[])o);
        im = Bitmap.FromStream(ms);
        }
    image1.Image = im;
    image1.Refresh();
    }

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