C# 不受信任的初始化-代码扫描问题

我在下面的代码中遇到一个高精度代码扫描问题。我需要做哪些更改才能解决此问题

private OleDbConnection importFileConnection;
private OleDbConnection ImportFileConnection
{
get
{
if (importFileConnection == null)
{ importFileConnection = new OleDbConnection(this.ConnectionString);
//getting scan issue in this line. }
//importFileConnection.Open();
return importFileConnection;
}
}

private string ConnectionString
{
get { return string.Format(ImportExportData.Default.ConnectionString, this.ServerFileName); }
}

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问题是String.format。声明带有out连接字符串的连接，然后提及连接属性