sql读写图片时Image.FromStream方法提示参数错误问题解决

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我们通常这么写

using (SqlDataReader drm = sqlComm.ExecuteReader())                     {                         drm.Read();//以下把数据库中读出的Image流在图片框中显示出来.                         MemoryStream ms = new MemoryStream((byte[])drm["Logo"]);                         Image img = Image.FromStream(ms);                         this.pictureBox1.Image = img;                     }

我的写数据

        private void btnOK_Click(object sender, EventArgs e)        {            string name = "";            if (tbxUserName.Text.Trim() == "")            {                MessageBox.Show("姓名不能为空，请重新输入！", "提示");                return;            }            else            {                name = tbxUserName.Text.Trim();            }            string group = "";            if (cbxGroup.Text.Trim() == "")            {                group = "未分组";            }            else            {                group = cbxGroup.Text.Trim();            }            string phone = tbxTel.Text.Trim();            string workunit = tbxWorkUnit.Text.Trim();            string email = tbxEmail.Text.Trim();            string qq = tbxQQ.Text.Trim();            byte[] b = null;            if (txtFilePath != "")            {                try                {                    FileStream fs = new FileStream(txtFilePath, FileMode.Open, FileAccess.Read);//类型为打开数据 权限为只读 不呢写数据                    int length = Convert.ToInt32(fs.Length);                    b = new byte[length];                    fs.Read(b, 0, length);//数据读入b数组中 从0号到length位                    fs.Close();//关闭输入输出流                }                catch (Exception ex)                {                    b = null;                    MessageBox.Show(ex.Message);                }            }            else             {                b = pixData;            }            try            {                using (SqlConnection connection = new SqlConnection(connectionString))                {                    //获取当前的数据在表中的ID                    SqlCommand commandInsert = new SqlCommand();                    commandInsert.Connection = connection;                    //connection.Close();                    connection.Open();                    //插入数据                    commandInsert.CommandText = "USE db_TXL UPDATE tb_BusicInfo set Groups= @Groups ,Name=@Name,WorkUnit=@WorkUnit,Phone=@Phone,Email=@Email,QQ=@QQ,Picture=@Picture";                    commandInsert.CommandText += "  where ID=@ID ";                    commandInsert.Parameters.Add("@ID", SqlDbType.Int);                    commandInsert.Parameters.Add("@Groups", SqlDbType.VarChar, 50);                    commandInsert.Parameters.Add("@Name", SqlDbType.VarChar, 20);                    commandInsert.Parameters.Add("@WorkUnit", SqlDbType.VarChar, 50);                    commandInsert.Parameters.Add("@Phone", SqlDbType.VarChar, 14);                    commandInsert.Parameters.Add("@Email", SqlDbType.VarChar, 50);                    commandInsert.Parameters.Add("@QQ", SqlDbType.VarChar, 20);                    commandInsert.Parameters.Add("@Picture", SqlDbType.Image);//Image的类型不能写错！！                    commandInsert.Parameters["@ID"].Value = ID;                  //  commandInsert.Parameters["@UserName"].Value = strUserName;                    commandInsert.Parameters["@Groups"].Value = group;                    commandInsert.Parameters["@Name"].Value = name;                    commandInsert.Parameters["@WorkUnit"].Value = workunit;                    commandInsert.Parameters["@Phone"].Value = phone;                    commandInsert.Parameters["@Email"].Value = email;                    commandInsert.Parameters["@QQ"].Value = qq;                    //commandInsert.Parameters[""].Value=;                    if (txtFilePath == "" && pixData==null)                    {                        commandInsert.Parameters["@Picture"].Value = DBNull.Value;//DBNull  不存在的值NULL                    }                    else                    {                        commandInsert.Parameters["@Picture"].Value = b;                    }                    commandInsert.ExecuteNonQuery();                    connection.Close();                    DialogResult = DialogResult.OK;                }            }            catch (Exception ex) { MessageBox.Show(ex.Message); }        }

我的读数据

     private void frmEdit_Load(object sender, EventArgs e)        {            try            {                using (SqlConnection connection = new SqlConnection(connectionString))                {                    string commandString = "select * from tb_BusicInfo where ID= " + ID.ToString() + " ";                    SqlCommand command = new SqlCommand(commandString, connection);                    connection.Open();                    SqlDataReader reader = command.ExecuteReader();                    if (reader.Read())                    {                        tbxUserName.Text = Convert.ToString(reader["Name"]);                        cbxGroup.Text = Convert.ToString(reader["Groups"]);                        tbxTel.Text = Convert.ToString(reader["Phone"]);                        tbxWorkUnit.Text = Convert.ToString(reader["WorkUnit"]);                        tbxEmail.Text = Convert.ToString(reader["Email"]);                        tbxQQ.Text = Convert.ToString(reader["QQ"]);                        if (reader["Picture"] == DBNull.Value)                        {                            pbxPicture.Image = TongXunLu.Properties.Resources.defaultPix;                        }                        else                        {                           // string a=reader["Picture"].ToString();                         //  byte[] b = (byte[])((reader["Picture"]));                           MemoryStream buf = new MemoryStream((byte[])reader["Picture"]);                            Image image = Image.FromStream(buf);                            Bitmap bt = new Bitmap(image);                            pbxPicture.Image = bt;                            //pbxPicture.Image = image;                          //  pbxPicture.Image = Image.FromStream(new MemoryStream(b));//把二进制流读出来??问题                        }                    }                    reader.Close();                    connection.Close();                }            }            catch (Exception ex)            {                MessageBox.Show(ex.Message);            }        }

读数据的时候，但是在写数据的时候可能发生了一些错误。

果然我在追寻byte[]的数组的时候发现写的时候有2万多个读的时候只有50个

于是我想可能是写的时候出了问题，于是

commandInsert.Parameters.Add("@Picture", SqlDbType.Image,50);

改为commandInsert.Parameters.Add("@Picture", SqlDbType.Image);

照片可以正常显示了

参考了http://blog.csdn.net/zystory/article/details/4399338

你存数据的时候出了问题，和读数据没有关系
new SqlParameter("@L_RolePic", SqlDbType.Image, 16) 改为 new SqlParameter("@L_RolePic", SqlDbType.Image),

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