如何检查连接字符串是否有效？

Question

我正在编写一个应用程序，其中用户手动提供连接字符串，我想知道是否有任何方法可以验证连接字符串 - 我的意思是检查它是否正确以及数据库是否存在。

Answer 1

您可以尝试连接吗？为了快速（离线）验证，也许使用

DbConnectionStringBuilder

来解析它......

    DbConnectionStringBuilder csb = new DbConnectionStringBuilder();
    csb.ConnectionString = "rubb ish"; // throws
    if (string.IsNullOrEmpty(csb.ConnectionString))
    {
        throw new ArgumentException("Connection string is invalid");
    }

但是要检查数据库是否存在，您需要尝试连接。当然，如果您知道提供商，那就最简单了：

    using(SqlConnection conn = new SqlConnection(cs)) {
        conn.Open(); // throws if invalid
    }

如果您只知道提供程序作为字符串（在运行时），则使用

DbProviderFactories

:

    string provider = "System.Data.SqlClient"; // for example
    DbProviderFactory factory = DbProviderFactories.GetFactory(provider);
    using(DbConnection conn = factory.CreateConnection()) {
        conn.ConnectionString = cs;
        conn.Open();
    }

Answer 2

试试这个。

    try 
    {
        using(var connection = new OleDbConnection(connectionString)) {
        connection.Open();
        return true;
        }
    } 
    catch {
    return false;
    }

Answer 3

如果目标是有效性而不是存在，则以下方法可以解决问题：

try
{
    var conn = new SqlConnection(TxtConnection.Text);
}
catch (Exception)
{
    return false;
}
return true;

Answer 4

对于 sqlite 使用此：假设文本框 txtConnSqlite 中有连接字符串

     Using conn As New System.Data.SQLite.SQLiteConnection(txtConnSqlite.Text)
            Dim FirstIndex As Int32 = txtConnSqlite.Text.IndexOf("Data Source=")
            If FirstIndex = -1 Then MsgBox("ConnectionString is incorrect", MsgBoxStyle.Exclamation, "Sqlite") : Exit Sub
            Dim SecondIndex As Int32 = txtConnSqlite.Text.IndexOf("Version=")
            If SecondIndex = -1 Then MsgBox("ConnectionString is incorrect", MsgBoxStyle.Exclamation, "Sqlite") : Exit Sub
            Dim FilePath As String = txtConnSqlite.Text.Substring(FirstIndex + 12, SecondIndex - FirstIndex - 13)
            If Not IO.File.Exists(FilePath) Then MsgBox("Database file not found", MsgBoxStyle.Exclamation, "Sqlite") : Exit Sub
            Try
                conn.Open()
                Dim cmd As New System.Data.SQLite.SQLiteCommand("SELECT * FROM sqlite_master WHERE type='table';", conn)
                Dim reader As System.Data.SQLite.SQLiteDataReader
                cmd.ExecuteReader()
                MsgBox("Success", MsgBoxStyle.Information, "Sqlite")
            Catch ex As Exception
                MsgBox("Connection fail", MsgBoxStyle.Exclamation, "Sqlite")
            End Try
          End Using

我认为你可以轻松地将其转换为 C# 代码