textbox中值与数据库的值比较，请指示，如何改？
　　　　　　　　string thiscncode=cn_SoftCodeTextBox.Text.Trim();
                OleDbConnection thisconn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + System.Windows.Forms.Application.StartupPath + "/CnEduCode.mdb");
                thisconn.Open();//打开连接
                OleDbCommand mycomm = new OleDbCommand();
                OleDbCommand thiscomm = thisconn.CreateCommand();

                = "select Cn_SoftCode from Cn_SoftWare where Cn_SoftCode =" + thiscncode + "";
               
               
               
                OleDbDataReader thisread = mycomm.ExecuteReader();

                if (thisread.Read())
                {
                    MessageBox.Show("软件编号已存在，请重新输入！");
                    thisread.Close();
                    return;
                }
                else
                {
                    string article = "insert into Cn_SoftWare (Cn_SoftName,Cn_Remark,Cn_SoftCode) values('" + cn_SoftNameTextBox.Text + "','" + cn_RemarkTextBox.Text + "' ,'" + cn_SoftCodeTextBox.Text + "')";

                    OleDbCommand comm = new OleDbCommand(article, thisconn);//创建Command命令对象

                    comm.ExecuteNonQuery();//执行命令

                    MessageBox.Show("添加完成！");

运行出错图如下：

[[it] 本帖最后由 brightmoon 于 2008-11-21 14:31 编辑 [/it]]

= "select Cn_SoftCode from Cn_SoftWare where Cn_SoftCode =" + thiscncode + "";
这句改为：
= "select Cn_SoftCode from Cn_SoftWare where Cn_SoftCode ='" + thiscncode + "'";

问题还是一样！在哪初始化？

string thiscncode=cn_SoftCodeTextBox.Text.Trim();
                OleDbConnection thisconn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + System.Windows.Forms.Application.StartupPath + "/CnEduCode.mdb");
                //thisconn.Open();//打开连接
                OleDbCommand mycomm = new OleDbCommand();
                mycomm.Connection = thisconn;//初始化connection
                //OleDbCommand thiscomm = thisconn.CreateCommand();

                = "select Cn_SoftCode from Cn_SoftWare where Cn_SoftCode ='" + thiscncode + "'";

                thisconn.Open();//打开连接
               
                OleDbDataReader thisread = mycomm.ExecuteReader();



问题解决，不管怎么样还是谢谢！