C# GetSchemaTable（）不返回IsKey属性

-你好，世界-

我正在做一个C#with ASP.NET项目，遇到了一个障碍。该项目是从表中动态加载元数据和记录以进行编辑，而无需静态定义可以编辑的表。因此，我需要获取不同表的模式/元数据

以下是我目前掌握的情况：

// initialize the connection
using (SqlConnection con = new SqlConnection(metadata.DatabaseString))
{
    // open the connection
    con.Open();

    // initialize a new SqlCommand to get the schema
    SqlCommand command = con.CreateCommand();
    command.CommandType = CommandType.Text;

    // 0 = 1 ensures it's always an empty data set
    command.CommandText = "SELECT * FROM " + metadata.TableName + " WHERE 0=1;";

    // set to SchemaOnly to improve performance (i think)
    SqlDataReader reader = command.ExecuteReader(CommandBehavior.SchemaOnly);

    // GetSchemaTable() gets the table's metadata
    DataTable dataTable = reader.GetSchemaTable();

    // loops through all the rows of the data table
    foreach (DataRow row in dataTable.Rows)
    {
        // field names found here: https://msdn.microsoft.com/en-us/library/system.data.datatablereader.getschematable(v=vs.110).aspx#Remarks
        metadata.ColumnMetadata.Add(new ColumnWrapper()
        {
            ColumnType = GetTypeFromSql(row.Field<string>("DataTypeName")),
            ColumnRawType = row.Field<string>("DataTypeName"),
            ColumnName = row.Field<string>("ColumnName"),
            ByteSize = row.Field<int>("ColumnSize"),
            IsKey = row.Field<bool?>("IsKey") ?? false
        });
    }
}

以下是我迄今为止所尝试的：

• 使用不同的表，得到相同的结果
• 访问

  dataTable.Columns[“IsKey”]

---

无论我往哪里看，我都找不到我需要的信息。有人知道是什么导致了这一切吗？如果相关，我将使用MDF文件和LocalDB进行数据库连接，而不是使用实时服务器。

休斯顿，我们起飞了

基于mjwills的帮助，我将代码更改为以下代码，从而使其正常工作：

// initialize the connection
using (SqlConnection con = new SqlConnection(metadata.DatabaseString))
{
    // open the connection
    con.Open();

    // initialize a new SqlCommand to get the schema. 0 = 1 ensures an empty data set
    SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM " + metadata.TableName + " WHERE 0=1", con);

    // GetSchemaTable() gets the table's metadata
    DataTable dataTable = new DataTable();

    // tell the adapater to fill in the missing schema
    adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;

    // fill the datatable with the schema
    adapter.FillSchema(dataTable, SchemaType.Mapped);

    // loops through all the rows of the data table
    foreach (DataColumn column in dataTable.Columns)
    {
        // field names found here: https://msdn.microsoft.com/en-us/library/system.data.datatablereader.getschematable(v=vs.110).aspx#Remarks
        metadata.ColumnMetadata.Add(new ColumnWrapper()
        {
            ColumnType = column.DataType,
            ColumnName = column.ColumnName,
            ByteSize = column.MaxLength,
            IsKey = dataTable.PrimaryKey.Contains(column)
        });
    }
}

我感谢那些对我最初的问题发表评论的人的帮助：）

有帮助吗？或者？可能的副本

// initialize the connection
using (SqlConnection con = new SqlConnection(metadata.DatabaseString))
{
    // open the connection
    con.Open();

    // initialize a new SqlCommand to get the schema. 0 = 1 ensures an empty data set
    SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM " + metadata.TableName + " WHERE 0=1", con);

    // GetSchemaTable() gets the table's metadata
    DataTable dataTable = new DataTable();

    // tell the adapater to fill in the missing schema
    adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;

    // fill the datatable with the schema
    adapter.FillSchema(dataTable, SchemaType.Mapped);

    // loops through all the rows of the data table
    foreach (DataColumn column in dataTable.Columns)
    {
        // field names found here: https://msdn.microsoft.com/en-us/library/system.data.datatablereader.getschematable(v=vs.110).aspx#Remarks
        metadata.ColumnMetadata.Add(new ColumnWrapper()
        {
            ColumnType = column.DataType,
            ColumnName = column.ColumnName,
            ByteSize = column.MaxLength,
            IsKey = dataTable.PrimaryKey.Contains(column)
        });
    }
}