Question

我试图为我设置为ComboBoxcolumn的datagridview列之一动态设置自定义下拉列表。当我运行应用程序时，我看到单元格中有值。但是，我看不到用户界面中弹出任何值。

field

当我连接调试器并检查（（DataGridViewComboBoxCell）_iprDataGridView.Rows [i] .Cells [16]）。DataSource = dt;我的项目集中有值，只是不会显示。

有关如何设置datagridview的更多代码。

private void CustomComboBoxColumns(string filter)
    {
        DataGridViewComboBoxColumn ComboBoxColumn = new DataGridViewComboBoxColumn();
        DataTable dt;
        ComboBoxColumn.HeaderText = "category";
        ComboBoxColumn.DataPropertyName = "category";
        ComboBoxColumn.ReadOnly = false;
        ComboBoxColumn.MaxDropDownItems = 100;
        ComboBoxColumn.AutoSizeMode = DataGridViewAutoSizeColumnMode.DisplayedCells;
        ComboBoxColumn.FlatStyle = FlatStyle.Flat;
        ComboBoxColumn.ValueMember = "category";
        ComboBoxColumn.DisplayMember = "category";
        _iprDataGridView.Columns.Insert(16, ComboBoxColumn);
        for (int i = 0; i < _iprDataGridView.Rows.Count; i++)
        {
            dt = GetDataForCategory(filter);
            ((DataGridViewComboBoxCell)_iprDataGridView.Rows[i].Cells[16]).DataSource = dt;
        }
    }

    private DataTable GetDataForCategory(string filter)
    {
        DbConnection db = new DbConnection();
        string connString = db.BuildConnectionString();
        DataTable dt = new DataTable();
        DataSet ds = new DataSet();
        string query = "Select category from cd_category where category like '%" + filter + "%' order by category";
        using (SqlConnection conn = new SqlConnection(connString))
        {
            if (conn.State == ConnectionState.Closed)
            {
                conn.Open();
            }

            SqlDataAdapter da = new SqlDataAdapter(query, conn);
            da.Fill(ds, "category");
            dt = ds.Tables["category"];
            da.Dispose();
            conn.Close();
        }
        return dt;
    }

我在考虑ConfigureTextBoxColumns（）之后，将创建将遍历datagridview的方法，并创建一个新的类别comboboxcolumn并根据另一个列的值插入一个新的comboboxcell。

这是有关如何为datagridview生成列的代码

_iprDataGridView.DataSource = _dbHelper.Select(queryBuild.ToString(), parameters, dbConnection);

            if (_iprDataGridView.DataSource == null) return;
            // In order to display and match the PIR table values, that are requried to be in
            // a comboBox menu, we need to remove the columns that have been populated and then
            // re-add them as comboBoxs
            ConfigureDataGridView();
            ConfigureComboBoxColumns();
            ConfigureTextBoxColumns();

我注释了他们的类别列，以插入我自己的类别。我正在更新这个不是我开发的应用程序。

Answer 1

您似乎正在尝试将数据绑定到控件。设置源之后，必须将其绑定。查看我所做的编辑。该链接提供了更多信息，并提供了一个示例 https://support.microsoft.com/en-us/help/307860/asp-net-data-binding-overview

    private void CustomComboBoxColumns(string filter)
        {
            DataGridViewComboBoxColumn ComboBoxColumn = new DataGridViewComboBoxColumn();
            DataTable dt;
            ComboBoxColumn.HeaderText = "category";
            ComboBoxColumn.DataPropertyName = "category";
            ComboBoxColumn.ReadOnly = false;
            ComboBoxColumn.MaxDropDownItems = 100;
            ComboBoxColumn.AutoSizeMode = DataGridViewAutoSizeColumnMode.DisplayedCells;
            ComboBoxColumn.FlatStyle = FlatStyle.Flat;
            ComboBoxColumn.ValueMember = "category";
            ComboBoxColumn.DisplayMember = "category";
            _iprDataGridView.Columns.Insert(16, ComboBoxColumn);
            for (int i = 0; i < _iprDataGridView.Rows.Count; i++)
            {
                dt = GetDataForCategory(filter);
             ((DataGridViewComboBoxCell)_iprDataGridView.Rows[i].Cells[16]).DataSource = dt;
             ((DataGridViewComboBoxCell)_iprDataGridView.Rows[i].Cells[16]).DataBind(); //this edit
            }
        }

我也强烈建议学习使用参数化查询来防止sql注入

已填充DataGridViewComboBoxCell，但不会显示内容

1 个答案: