Question

我正在尝试从我的datagridview获取图像并获得成功，但如果某些记录没有图像或（null），那么我得到错误（无法将类型＆＃39; System.DBNull＆＃39;的对象转换为输入＆＃39; System.Byte []＆＃39;。）。以下是我的代码：

 private void dgridEmployees_SelectionChanged(object sender, EventArgs e)
    {
        DataGridViewCell cell = null;
        foreach (DataGridViewCell selectedCell in dgridEmployees.SelectedCells)
        {
            cell = selectedCell;
            break;

        }

        if (cell != null)
        {
            DataGridViewRow row = cell.OwningRow;
            lbl_ID.Text = row.Cells[0].Value.ToString();
            tboxEmployeeID.Text = row.Cells[1].Value.ToString();
            tboxEmployeeName.Text = row.Cells[2].Value.ToString();
            dtboxJoiningDate.Text = row.Cells[3].Value.ToString();
            tboxDepartment.Text = row.Cells[4].Value.ToString();
            tboxPath.Text = row.Cells[5].Value.ToString();

            byte[] img = (byte[])dgridEmployees.CurrentRow.Cells[6].Value;
            if (img == null)
                pictureBox1.Image = null;
            else
            {
                MemoryStream ms = new MemoryStream(img);
                pictureBox1.Image = Image.FromStream(ms);
            }


        }

请为我的上述代码提出任何解决方案？

Answer 1

首先，您需要检查单元格是否包含值。在这种情况下，它的值将是DBNull.Value（DBNull类的单个实例）。如果比较为假，则只能将其值转换为byte[]。

if (dgridEmployees.CurrentRow.Cells[6].Value != DBNull.Value)
{
    byte[] img = (byte[])dgridEmployees.CurrentRow.Cells[6].Value;
    MemoryStream ms = new MemoryStream(img);
    pictureBox1.Image = Image.FromStream(ms);
}
else
{
    pictureBox1.Image = null;
}

C＃ - 如果数据库记录为空，如何从datagridview处理picturebox

1 个答案: