Question

我通过以下方法将DataTable绑定到DGV：

public DataTable GetDgvData(string selectQuery, string companyFilter, string categoryFilter, string idFilter)
{
    using (NpgsqlConnection conn = new NpgsqlConnection(connString))
    using (NpgsqlCommand cmd = new NpgsqlCommand(selectQuery, conn))
    {
        cmd.Parameters.Add(new NpgsqlParameter("company", companyFilter));
        if (!string.IsNullOrEmpty(idFilter)) cmd.Parameters.Add(new NpgsqlParameter("idList", idFilter));
        if (categoryFilter != "All Categories") cmd.Parameters.Add(new NpgsqlParameter("category", categoryFilter));

        DataSet ds = new DataSet();

        conn.Open();

        using (NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd))
        {
            da.Fill(ds);
        }
        conn.Close();

        return ds.Tables[0];
    }
}

最初，它没有最后一个参数string idFilter或第二个cmd.Parameters.Add() line。而且对该方法的所有调用都运行良好，并填充了使用该方法的DGV。

然后我向WinForm中添加了搜索功能，该功能在DGV的DataTable中搜索用户输入的字符串，遍历DataTable，为具有搜索字符串的行建立记录ID的列表，然后我需要仅使用在DataTable的单元格中具有搜索字符串的行来重建DGV。

这是该搜索过程的功能：

private void btnSearch_Click(object sender, EventArgs e)
{
    string searchText = txtSearchCatsGrid.Text;
    string idToAddToList = "";
    string tempIdList = "";
    string idListForQuery = "";

    DataTable dt = ((DataTable)dgvCategories.DataSource);
    string cellValue;
    int rowIndex;
    int columnIndex;

    for (rowIndex = 0; rowIndex <= dt.Rows.Count - 1; rowIndex++)
    {
        for (columnIndex = 0; columnIndex <= dt.Columns.Count - 1; columnIndex++)
        {
            cellValue = dt.Rows[rowIndex][columnIndex].ToString();

            if (searchText == cellValue)
            {
                // Set corresponding dgvCategories cell's background color to yellow
                dgvCategories[columnIndex, rowIndex].Style.BackColor = Color.Yellow;

                idToAddToList = dt.Rows[rowIndex][0].ToString();
            }
        }

        if (!string.IsNullOrEmpty(idToAddToList) && !tempIdList.Contains(idToAddToList)) tempIdList += idToAddToList + ",";

    }

    if (!string.IsNullOrEmpty(tempIdList))
    {
        idListForQuery = tempIdList.Remove(tempIdList.Length - 1, 1);
    }

    Console.WriteLine("idListForQuery: " + idListForQuery);

    // Refresh dgvCategories with just rows from search, using idListForQuery

    string companyFilter = cboSelectCompany.Text;
    string categoryFilter = cboSelectCategory.Text;

    db categoriesData = new db();

    if (categoryFilter == "All Categories")
    {
        string catsQuery = "SELECT id, category, source_company, old_value, old_desc, new_value, new_desc, reference1, reference2 " +
                            "FROM masterfiles.xref"+
                            " WHERE company_name = @company" +
                                " AND id IN (@idList)" +
                            " ORDER BY category, old_value, source_company";
        this.dtCategories = categoriesData.GetDgvData(catsQuery, companyFilter, categoryFilter, idListForQuery);
    }
    else
    {
        string catsQuery = "SELECT id, category, source_company, old_value, old_desc, new_value, new_desc, reference1, reference2 " +
                            "FROM masterfiles.xref" +
                            " WHERE company_name = @company" +
                                " AND category = @category" +
                                " AND id IN (@idList)" +
                            " ORDER BY old_value, source_company";
        this.dtCategories = categoriesData.GetDgvData(catsQuery, companyFilter, categoryFilter, idListForQuery);
    }

    // TODO: Need to check this.dtCategories.Rows.Count

    dgvCategories.DataSource = this.dtCategories;

    if (dtCategories.Rows.Count == 0)
    {
        return;
    }
    else
    {
        dgvCategories.Columns[0].Visible = false;
        dgvCategories.Rows[0].Cells[0].Selected = false;
    }
}

传递给GetDgvData()函数的ID列表是正确的，据我所知，其实现与公司和类别过滤器完全相同。加载表单并初始填充DGV时，程序运行正常（我将空字符串传递给GetDgvData()，以进行其他所有调用），但是当我使用该搜索功能时，在{ {1}}，它表示“ Npgsql.PostgresException：'42883：运算符不存在：integer = text'”。

'selectQuery'看起来像这样：

da.Fill(ds)

和idList看起来像这样：

SELECT id, category, source_company, old_value, old_desc, new_value, new_desc, reference1, reference2 FROM masterfiles.xref WHERE company_name = @company AND id IN (@idList) ORDER BY category, old_value, source_company

我将异常解释为ID必须是整数，但是我无法弄清楚如何将ID列表作为整数传递给1475,1476,1477,1331,1332方法-即使那是问题在这里。我是否需要将ID列表构建为数组并将列表以这种方式传递给GetDgvData()？还是在GetDgvData()中将每个ID都转换为整数？

向NpgsqlCommand添加查询参数会导致异常

0 个答案: