retreive bitmap image from database.

Ramu Eppakayala

i am performing search operation and retreiving image from database to pictureEdit control. I stored image as varchar(4000). and images are storing in the format of System.Drawing.Bitmap.I am getting Error as -> "Unable to cast object of type 'System.String' to type 'System.Byte[]".

private void btnSearch_Click(object sender, EventArgs e)
{
byte[] getImg = new byte[0];
SqlDataAdapter dataAdapter = new SqlDataAdapter("select sid,sname,fathername,contactno,address,sphoto from Student where sclass='" + lukupClass.Text + "' and ssection='" + lukupSection.Text + "' and sname='" + textBox1.Text + "'", sqlConnection);
DataTable dt = new DataTable();
dataAdapter.Fill(dt);
if (dt.Rows.Count > 0)
{
txtID.Text = dt.Rows[0]["sid"].ToString();
txtStudentName.Text = dt.Rows[0]["sname"].ToString();
txtFatherName.Text = dt.Rows[0]["fathername"].ToString();
txtContactNo.Text = dt.Rows[0]["contactno"].ToString();
memoAddress.Text = dt.Rows[0]["address"].ToString();
getImg = ((byte[])dt.Rows[0]["sphoto"]);
byte[] imgData = getImg;
MemoryStream stream = new MemoryStream(imgData);
picStudent.Image = Image.FromStream(new MemoryStream(getImg));
}
else
{
MessageBox.Show("No Data Found with this Name.");
}

7 Replies

Know the answer? Post it — somebody with the same question will find it here.

Jignesh Kumar6y ago
Hi,

Please use this link,

https://www.c-sharpcorner.com/UploadFile/0c1bb2/uploading-and-displaying-images-from-database-using-Asp-Net/
https://www.aspsnippets.com/Articles/Save-and-Retrieve-images-from-database-in-ASPNet.aspx
Amit Gupta6y ago
Which platform you are using, winForms, WPF or web?

I think you are missing some namespace (do add System.Drawing), read the article carefully, as it shows how to store and fetch the image from database.

Good Luck
Ramu Eppakayala6y ago
1. byte[] getImg = new byte[0];
2. SqlDataAdapter dataAdapter = new SqlDataAdapter("select sid,sname,fathername,contactno,address,sphoto from Student where sclass='" + lukupClass.Text + "' and ssection='" + lukupSection.Text + "' and sname='" + textBox1.Text + "'", sqlConnection);
3. DataTable dt = new DataTable();
4. dataAdapter.Fill(dt);
5. if (dt.Rows.Count > 0)
6. {
7. txtID.Text = dt.Rows[0]["sid"].ToString();
8. txtStudentName.Text = dt.Rows[0]["sname"].ToString();
9. txtFatherName.Text = dt.Rows[0]["fathername"].ToString();
10. txtContactNo.Text = dt.Rows[0]["contactno"].ToString();
11. memoAddress.Text = dt.Rows[0]["address"].ToString();
12. getImg = ((byte[])dt.Rows[0]["sphoto"]);
13. byte[] imgData = getImg;
14. MemoryStream stream = new MemoryStream(imgData);
15. picStudent.Image = Image.FromStream(stream);
16. }
at FromStream am getting error as "Parameter is not valid".

Ramu Eppakayala6y ago

i converted varchar(4000) to varbinary(MAX) while executing sql query i am getting error as "Implicit conversion from data type varchar to varbinary(max) is not allowed. Use the CONVERT function to run this query"

Amit Gupta6y ago

1. Don't use varchar in your database.

2. If it is still string datatype then you have to convert it explicitly like Convert.ToBytes(...) and not (byte[]).

Read the below article

https://www.c-sharpcorner.com/article/save-image-in-row-format-bytes-into-database-and-fetch-from-database-in-c-sharp-wi/

Ramu Eppakayala6y ago

i am getting same error

Amit Gupta6y ago

Replace this line

MemoryStream stream = new MemoryStream(imgData);
picStudent.Image = Image.FromStream(new MemoryStream(getImg));

with this one

MemoryStream stream = new MemoryStream(imgData);
picStudent.Image = Image.FromStream(stream );