winform Combox绑定数据并根据value值选中项

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DataTable dtsingletype = singletypeBal.GetDataTable("");            comboBox1.DataSource = dtsingletype;            comboBox1.DisplayMember = "TypeName";            comboBox1.ValueMember = "ID";

选中项：

if (parentid != "")            {                comboBox1.SelectedValue = parentid;//根据ID值选中该项            }

根据text值选中项：

comboBox1.SelectedIndex=comboBox1.FindString("汽配");

combox联动：

int zmlflag = 0;        private void frmMain_Load(object sender, EventArgs e)        {            DataTable dtsingletype = singletypeBal.GetDataTable("");            cbZML.DataSource = dtsingletype;//绑定数据时会触发selectedindexchanged事件，所以在事件中判断当页面加载完以后再更新下一级数据，且判断选中值是否为空，数据源是否为空            cbZML.DisplayMember = "TypeName";            cbZML.ValueMember = "ID";            zmlflag = 1;        }

private void cbZML_SelectedIndexChanged(object sender, EventArgs e)        {            if (flag>0) //页面加载以后 选中项改变再更改数据            {                if (cbZML.DataSource != null && cbZML.SelectedValue!=null && cbZML.SelectedValue.ToString().Trim()!="")                {                    DataTable dtsinglesmalltype = singletypesmallBal.GetDataTable(" typeid=" + cbZML.SelectedValue.ToString().Trim());                    cbPP.DataSource = dtsinglesmalltype;                    cbPP.DisplayMember = "TypeName";                    cbPP.ValueMember = "ID";                }            }        }

用参数更新数据时，语句正确，但是更新失败：

StringBuilder strSql = new StringBuilder();            strSql.Append("update tb_SingleTypeSmall set ");            strSql.Append("TypeName=@TypeName,");            strSql.Append("TypeNote=@TypeNote,TypeID=@TypeID");            strSql.Append(" where ID=@ID");            OleDbParameter[] parameters = {new OleDbParameter("@TypeName", OleDbType.VarChar,50),new OleDbParameter("@TypeNote", OleDbType.VarChar,200),new OleDbParameter("@TypeID", OleDbType.Integer,4),//因为@TypeID和@ID换了下位置，导致更新失败，看来这个位置也得对应                    new OleDbParameter("@ID",OleDbType.Integer,4)            };            parameters[0].Value = model.TypeName;            parameters[1].Value = model.TypeNote;            parameters[2].Value = model.TypeID;            parameters[3].Value = model.ID;