无法在 C# 中删除数据表中的空列名

Question

我有一个 Excel 业务用户将更新并将其发送给我们。 Blue Prism 机器人将选择文件并上传到 SQL 数据库 table 使用代码阶段（使用代码阶段要快得多）。我已经编写了 C# 代码来执行此操作，但是大多数情况下由于列中的白色 space 而失败。

结果是当代码使用已用范围时它也采用白色 space 并创建列名称为 F16、F17 的数据 table ...（当列数为 15 时）

我想动态地处理这个问题。即不管列数和白色 space 列数，代码应该通过从数据 tables

中删除那些白色 space 列来工作

我已经编写了代码来处理这个问题，但是没有用。它抛出一个错误：

Collection was modified; enumeration operation might not execute [duplicate]

try
{
    string excelConnectionString = string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=Excel 8.0", Path);
    using (OleDbConnection xlConnection = new OleDbConnection(excelConnectionString)) 
    { 
        OleDbCommand oleDbCmd = new OleDbCommand ("Select * FROM [" + SheetName + "$]", xlConnection); 

        xlConnection.Open(); 

        // Create DbDataReader to Data Worksheet 
        using (DbDataReader dbDtRdr = oleDbCmd.ExecuteReader()) 
        { 
                //Remove Empty Rows
                var dtTable = new DataTable();
                dtTable.Load(dbDtRdr);

                for (int i = dtTable.Rows.Count - 1; i>=0;i--)
                {
                    if(dtTable.Rows[i][1] == DBNull.Value)
                        dtTable.Rows[i].Delete();
                }

                dtTable.AcceptChanges();

                //Remove Empty Columns
                int z = 1;

                foreach(DataRow r in dtTable.Rows)
                {
                    foreach(DataColumn c in dtTable.Columns)
                    {   
                        if (c.ColumnName=="F" + z.ToString())
                            dtTable.Columns.Remove(c.ColumnName);
                    }
                }

                dtTable.AcceptChanges();

                // SQL Server Connection String 
                string sqlConnectionString = @"Data Source=" + SQLServerName + ";Initial Catalog=" + SQLDBName + ";Integrated Security=True"; 

                // Bulk Copy to SQL Server 
                using (SqlBulkCopy bulkCopy = new SqlBulkCopy(sqlConnectionString)) 
                { 
                    bulkCopy.DestinationTableName = TableName; 
                    bulkCopy.WriteToServer(dtTable); 
                }
        } 

        xlConnection.Close();
    }

    Success = true;
    Message = "Success";
}
catch (System.IO.IOException e)
{
    Message = e.Message;
    Success = false;        
}

看来我无法使用上述代码中的删除命令删除数据中的任何列table

如果有人能帮助我，那将是很大的帮助。

注意：我尝试使用 For Next 循环向后重复它，如下所示，但仍然遇到问题

                for (int z = dtTable.Columns.Count - 1; z>=0;z--)
                    {
                            if (dtTable.Columns[z].ColumnName.ToString()=="F" + (z).ToString())
                            dtTable.Columns.Remove(dtTable.Columns[z].ColumnName.ToString());
                        }
                        dtTable.AcceptChanges();

Answer 1

根据下面给出的 JohnPete22 的评论，它工作正常

If you think about it, you're looping through each DataColumn and then also removing from that Collection at the same time, which cannot happen. You need a For loop, and then loop backwards to 0 (which you can see happening just above that line). General rule of thumb: not a good idea to remove from a collection you're looping through at the same time, unless you work your way backwards

还需要注意以下几点

I have tried using John's solution earlier but didn't work. Then I realised that I have used if (dtTable.Columns[z].ColumnName.ToString()=="F" + (z).ToString()) however it should be if (dtTable.Columns[z].ColumnName.ToString()=="F" + (z+1).ToString()) since the additional white space name using the index of 1 and not 0 for columns.

无法在 C# 中删除数据表中的空列名

Unable to remove empty column names in the datatable in C#

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oledbcommand