高手帮我看看代码,并发冲突 ,是什么原因呀?

创建DataSet-----------------------------------
DepData=new DepartmentData();
DataRow row=DepData.Tables[DepartmentData.TBLDEPARTMENN_TABLE].NewRow();
row[DepartmentData.DEP_NAME_FIELD]=txtDepName.Text.Trim();
row[DepartmentData.DEP_CODE_FIELD]=txtDepCode.Text.Trim();
row[DepartmentData.DEP_DESC_FIELD]=txtDepCode.Text.Trim(); row[DepartmentData.DEP_STATUS_FIELD]=depStatus; DepData.Tables[DepartmentData.TBLDEPARTMENN_TABLE].Rows.Add(row);

DepData.AcceptChanges(); row[DepartmentData.DEP_ID_FIELD]=Convert.ToInt32(Request.QueryString["id"]); retVal=objFacade.ModifyDepartment(DepData);
-----------------------------------------------
public bool UpdataDepartment(DepartmentData depData)
{
if(sqlAdp==null)
{
throw new System.ObjectDisposedException( GetType().FullName );
} sqlAdp.UpdateCommand=GetUpdataDepCmd(); sqlAdp.Update(depData,DepartmentData.TBLDEPARTMENN_TABLE); if(depData.HasErrors)
{
depData.Tables[DepartmentData.TBLDEPARTMENN_TABLE].GetErrors()[0].ClearErrors(); return false;
}
else
{
depData.AcceptChanges(); return true;
}
}
public SqlCommand GetUpdataDepCmd()
{
if(sqlUpdateCmd!=null)
{
sqlUpdateCmd.CommandText="UpdataDepartment";
sqlUpdateCmd.Connection=new SqlConnection(DuwamishConfiguration.ConnectionString);
sqlUpdateCmd.CommandType=CommandType.StoredProcedure;
SqlParameterCollection sqlParams=sqlInsertCmd.Parameters;
sqlParams.Add(new SqlParameter(DEP_ID_PARM,SqlDbType.Int,4));
sqlParams.Add(new SqlParameter(DEP_NAME_PARM,SqlDbType.NVarChar,200));
sqlParams.Add(new SqlParameter(DEP_CODE_PARM,SqlDbType.NVarChar,50));
sqlParams.Add(new SqlParameter(DEP_DESC_PARM,SqlDbType.NVarChar,200));
sqlParams.Add(new SqlParameter(DEP_STATUS_PARM,SqlDbType.NVarChar,50)); sqlParams[DEP_ID_PARM].SourceColumn=DepartmentData.DEP_ID_FIELD; sqlParams[DEP_NAME_PARM].SourceColumn=DepartmentData.DEP_NAME_FIELD;
sqlParams[DEP_CODE_PARM].SourceColumn=DepartmentData.DEP_CODE_FIELD;
sqlParams[DEP_DESC_PARM].SourceColumn=DepartmentData.DEP_DESC_FIELD;
sqlParams[DEP_STATUS_PARM].SourceColumn=DepartmentData.DEP_STATUS_FIELD;
}
return sqlUpdateCmd;
}出错信息是----------------------------
并发冲突: UpdateCommand 影响 0 个记录。