c# - 以编程方式添加到 DataGridView 单元格的 ComboBox 在单元格单击时不展开

Question

我在 C# WinForms 项目中有一个 DataGridView，其中当用户单击某些 DGV 单元格时，该单元格会更改为 DataGridViewComboBoxCell 并且 ComboBox 中填充了一些值供用户选择。以下是 DataGridView_Click 事件的表单代码:

private void dgvCategories_Click(Object sender, DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex == 5 && !(dgvCategories.Rows[e.RowIndex].Cells[e.ColumnIndex].GetType().Name == "DataGridViewComboBoxCell"))
    {
        // Bind combobox to dgv and than bind new values datasource to combobox
        DataGridViewComboBoxCell cboNewValueList = new DataGridViewComboBoxCell();

        // Get fields to build New Value query
        List<string> lsNewValuesResult = new List<string>();
        string strCategory = dtCategories.Rows[e.RowIndex][1].ToString();
        string strCompanyName = cboSelectCompany.Text;
        string strQueryGetNewValuesValidationInfo = "SELECT validationdb, validationtable, validationfield, validationfield2, validationvalue2" +
                                                " FROM masterfiles.categories" +
                                                " WHERE category = @category";
                                                //" WHERE category = '" + strCategory + "'";

        // Pass validation info query to db and return list of New Values
        db getListOfNewValues = new db();
        lsNewValuesResult = getListOfNewValues.GetNewValuesList(strQueryGetNewValuesValidationInfo, strCategory, strCompanyName);

        //Populate the combobox with the list of New Values
        foreach (string strListItem in lsNewValuesResult)
        {
            cboNewValueList.Items.Add(strListItem);
        }

        // 
        dgvCategories[e.ColumnIndex, e.RowIndex] = cboNewValueList;

    }
}

这是 db 类中填充 ComboBox 的代码(出于本问题的目的，这可能没有必要包括在内，但为了完整起见，我将其包括在内，以防它相关):

public List<string> GetNewValuesList(string strValidationInfoQuery, string strCategory, string strCompanyName)
{
    List<string> lsValidationInfo = new List<string>();
    List<string> lsNewValuesList = new List<string>();

    using (NpgsqlConnection conn = new NpgsqlConnection(connString))
    using (NpgsqlCommand cmd = new NpgsqlCommand(strValidationInfoQuery, conn))
    {
        cmd.Parameters.AddWithValue("category", strCategory);

        conn.Open();

        using (NpgsqlDataReader reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                int intReaderIndex;
                for (intReaderIndex = 0; intReaderIndex <= reader.FieldCount - 1; intReaderIndex++)
                {

                    // reader indexes 3 & 4 correspond to categories.validationfield2 and validationvalue2, which can be null
                    if (string.IsNullOrEmpty(reader[intReaderIndex].ToString()))
                    {
                        lsValidationInfo.Add("");
                    }
                    else
                    {
                        lsValidationInfo.Add(reader.GetString(intReaderIndex));
                    }
                    //Console.WriteLine("reader index " + intReaderIndex + ": " + reader.GetString(intReaderIndex));
                }
            }
        }
    }

    string strValidationDb = lsValidationInfo[0];
    string strValidationTable = lsValidationInfo[1];
    string strValidationField = lsValidationInfo[2];
    string strValidationField2 = lsValidationInfo[3];
    string strValidationValue2 = lsValidationInfo[4];

    string strQueryGetNewValues = "SELECT DISTINCT " + strValidationField +
                        " FROM " + strValidationDb + "." + strValidationTable +
                        " WHERE company_id = (SELECT id FROM company WHERE name = '" + strCompanyName + "')";

    if (!string.IsNullOrEmpty(strValidationField2) && !string.IsNullOrEmpty(strValidationValue2)) strQueryGetNewValues += " AND " + strValidationField2 + " = '" + strValidationValue2 + "'";

    strQueryGetNewValues += " ORDER BY " + strValidationField;

    using (NpgsqlConnection conn = new NpgsqlConnection(connString))
    using (NpgsqlCommand cmd = new NpgsqlCommand(strQueryGetNewValues, conn))
    {
        conn.Open();

        using (NpgsqlDataReader reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                int intReaderIndex;
                for (intReaderIndex = 0; intReaderIndex <= reader.FieldCount - 1; intReaderIndex++)
                {
                    // reader indexes 3 & 4 correspond to categories.validationfield2 and validationvalue2, which can be null
                    if (string.IsNullOrEmpty(reader[intReaderIndex].ToString()))
                    {
                        lsNewValuesList.Add("");
                    }
                    else
                    {
                        lsNewValuesList.Add(reader.GetString(intReaderIndex));
                    }
                    Console.WriteLine("reader index " + intReaderIndex + ": " + reader.GetString(intReaderIndex));
                }
            }
        }
    }

    return lsNewValuesList;
}

组合框正在填充，因为我可以在 _Click 方法中访问 lsNewValuesResult 中的项目。 DGV 编辑模式设置为 EditOnEnter。我尝试了 EditOnKeyrinkle，但这并没有导致组合框在鼠标单击时展开。

这就是单击单元格并且填充 CBO 并将其添加到 DGV 单元格时组合框的外观:

那是在我单击两个单元格之后。

[已解决]

请参阅下面我的回答。

不幸的是解决这个问题revealed a new issue .

Answer 1

我要公开承认我很愚蠢:

出于该项目所需的设计和功能原因，我手动设置 DGV 列的宽度和名称，并且我还需要第 2 到第 4 列ReadOnly = true。嗯，我无意中设置了第 5 列 - 这个问题即将要 ReadOnly = true 的列。

感谢大家尝试回答。这只是提醒我们，如此简单的事情如何会导致看似大的问题，而且很容易被忽视!