为什么使用定义列表（DL，DD，DT）代替HTML表单而不是表格？(Why use definition lists (DL,DD,DT) tags for HTML forms instead of tables?)

 在字符串之前使用@时，不需要再次转义反斜杠。 LIKE的占位符是％，而不是*。 
 
 所以尝试： 
 
string query = @"SELECT COUNT(*) FROM table WHERE path LIKE '%\\\\server\\dir\\%'";
 
 要避免所有转义，请考虑使用SQL参数。 
 
 PS：table是保留关键字。 您不应该为表格命名，这将始终导致问题。 

So Ms Access use * as a wildcard like T_D indicated and which is what my valide query use in MS Access. BUT like HansUp indicated C# OleDb API still uses ANSI wild cards.
 
But small correction even to that answer would be to escape the query in c#. So query returning valid answer is:
 
string query = "SELECT COUNT(*) FROM Settings WHERE path LIKE '%\\\\server\\dir\\%'";
OR
string query = @"SELECT COUNT(*) FROM Settings WHERE path LIKE '%\\server\dir\%'";
-> returns Count(*) = 3
 
HansUp also pointed that using ALIKE instead of LIKE % also works in MS Access so that way query is compatible with ANSI wildcard %
 
So here is my working solution (with command parameters):
 
string destFolder = @"\\server\\dir\";
string query = "SELECT COUNT(*) FROM Settings WHERE path LIKE @destFolder;";

using (OleDbConnection connection = new OleDbConnection(mdbfile))
{
    using (OleDbCommand command = new OleDbCommand(query, connection))
    {
        command.Parameters.AddWithValue("@destFolder", "%" + destFolder + "%");
        try
        {
            connection.Open();
            if ((int)command.ExecuteScalar() == 3)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        catch (OleDbException ex)
        {
            //handle OleDb error
            return false;
        }
    }
}