C# 将 Listbox1 中的值用于 SQL 查询以过滤 Listbox2

Question

我有三个 SQL 表 - Team（Id，Name），Player（Id，Name）和 TeamPlayer（Id，TeamID，PlayerID）。 我的表单上还有两个 ListBox，并且希望在第一个 ListBox 上选择项目时过滤第二个 ListBox。

这主要是设置，但我遇到的问题是代码不喜欢在注释行的 LstTeams_SelectedIndexChanged 方法中传递给它的值。

private void Form1_Load(object sender, System.EventArgs e)
    {
        showTeams();
    }

    private void showTeams()
    {
        // Create the SQL Query, and an SqlDataAdapter using this query and sqlConnection declared earlier
        string query = "select * from Team";
        SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(query, sqlConnection);

        // Get the 'Team' Table and Fill it
        DataTable teamTable = new DataTable();
        sqlDataAdapter.Fill(teamTable);

        // Populate the 'Team' ListBox with the 'Team' Table
        lstTeams.DataSource = teamTable.DefaultView;
        lstTeams.DisplayMember = "Name";
        lstTeams.ValueMember = "Id";
    }

    private void LstTeams_SelectedIndexChanged(object sender, System.EventArgs e)
    {
        string TeamID = lstTeams.GetItemText(lstTeams.SelectedValue);
        MessageBox.Show("TeamID: " + TeamID);

        // Create the SQL Query, and an SqlDataAdapter using this query and sqlConnection declared earlier
        string query = "select * from Player p inner join TeamPlayer tp on p.Id = tp.PlayerID where tp.TeamID = @TeamID";

        SqlCommand sqlCommand = new SqlCommand(query, sqlConnection);
        sqlCommand.Parameters.AddWithValue("@TeamID", lstTeams.SelectedValue); // this
        SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sqlCommand); // causes the dataadapter to error

        // Get the 'Team' Table and Fill it
        DataTable teamTable = new DataTable();
        sqlDataAdapter.Fill(teamTable);

        // Populate the 'Team' ListBox with the 'Team' Table
        lstPlayers.DataSource = teamTable.DefaultView;
        lstPlayers.DisplayMember = "Name";
    }

我的错误是：

System.ArgumentException: 'No mapping exists from object type System.Data.DataRowView to a known managed provider native type.'

我已经查找了一些解决方案，但无法获得有效的结果。

感谢您提供的任何帮助:)。

Answer 1

经过进一步研究并从对我的问题的评论中获得了一些指导，我在以下方面取得了成功：

DataRowView data = lstTeams.SelectedItem as DataRowView;
int TeamID = int.Parse(data["Id"].ToString());

string query = "select * from Player p inner join TeamPlayer tp on p.Id = tp.PlayerID where tp.TeamID = " + TeamID;

在 ListBox1.SelectedIndexChanged 方法内部。