检测如果一个IDataReader的包含迭代之前某一领域 [英] Detecting if an IDataReader contains a certain field before iteration

问题描述

所以我使用的IDataReader来滋润一些业务对象，但我不运行时知道字段将在读者什么。不在阅读器的任何字段将被留为空所产生的对象上。

So I'm using an IDataReader to hydrate some business objects, but I don't know at runtime exactly what fields will be in the reader. Any fields that aren't in the reader would be left null on the resulting object. How do you test if a reader contains a specific field without just wrapping it in a try/catch?

推荐答案

这应该做的绝招：

    Public Shared Function ReaderContainsColumn(ByVal reader As IDataReader, ByVal name As String) As Boolean
        For i As Integer = 0 To reader.FieldCount - 1
            If reader.GetName(i).Equals(name, StringComparison.CurrentCultureIgnoreCase) Then Return True
        Next
        Return False
    End Function

或（在C＃）

public static bool ReaderContainsColumn(IDataReader reader, string name)
{
    for (int i = 0; i < reader.FieldCount; i++) {
        if (reader.GetName(i).Equals(name, StringComparison.CurrentCultureIgnoreCase)) return true; 
    }
    return false;
}

：O）

:o)

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