HYPDM.WinUI.ProductsAndParts.Parts.PartsStructAddForm.selectMaterail C# (CSharp) Method

        private void selectMaterail()
        {
            string t_materailId=null;
            for (int i = 0; i < dgv_MaterialList.Rows.Count; i++)
            {
                DataGridViewCheckBoxCell checkcell = (DataGridViewCheckBoxCell)dgv_MaterialList.Rows[i].Cells[0];
                Boolean flag = Convert.ToBoolean(checkcell.Value);
                if (flag)
                {
                    t_materailId = dgv_MaterialList.Rows[i].Cells["MATERIALID"].Value.ToString().Trim();
                }
            }
            if (t_materailId == null) { MessageBox.Show("请选择一个材料"); return; }

            if (filterSelect(t_materailId) == -1)
            {
                MessageBox.Show("已经在产品结构中"); return;
            }

            HYPDM.Entities.PDM_STRUCT temp_struct = new HYPDM.Entities.PDM_STRUCT();
            temp_struct.OBJECTID = this.copy_Product.PRODUCTID;
            temp_struct.ASSOBJECTID = t_materailId;

            StructAddForm o = new StructAddForm(temp_struct, m_assoID, this.m_assoType);
            o.StartPosition = FormStartPosition.CenterParent;
            o.ShowDialog();
        }