Question

我有以下法典:

foreach(string reelid in unValidatedFeedersOnMachine.Keys)
{
    _sqlString.Append("CompID =  ").Append(reelid).Append("  ");
}

在此表格中,除最后一条外,我需要添加“<代码>>.Appened(或)。

谁能知道什么时候?

Answer 1

我会以其他方式处理第一个例外,因为例外更为简单:

bool first = true;
foreach(string reelid in unValidatedFeedersOnMachine.Keys)
{
   if(first) {first = false;}
   else {_sqlString.Append(" or ";}
    _sqlString.Append("CompID =  ").Append(reelid).Append("  ");
}

or in .NET 4.0 just use:

string s = string.Join(" or ",
           from key in unValidatedFeedersOnMachine.Keys
           select "CompID =  " + reelid + " ");

如果是这样的话,将改为<代码> 页: 1

string s = "CompID IN (" + string.Join(","
           from key in unValidatedFeedersOnMachine.Keys
           select " " + reelid + " ") + ")";

Answer 2

怎么做呢?

string query = string.Join(" or ", unValidatedFeedersOnMachine.Keys.Select(x => "CompID =  " + x + " ").ToArray())

P.S.
If you re targeting .net 4.0, you can skip the .ToArray()

Answer 3

我倾向于这样做。

var _sqlString = new StringBuilder();
foreach(string reelid in unValidatedFeedersOnMachine.Keys) {                     
    if(_sqlString.ToString().Length != 0) {
        _sqlString.Appened(" or ")
    }
    _sqlString.Append("CompID =  ").Append(reelid).Append("  ");
}

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