如何通过从组合框中选择任何表来填充DataGridView

Question

我已经使用以下代码在组合框中显示我的SQL数据库表的名称。

现在我希望当我从组合框中单击任何这些表名时，我的DGV将填充该表的内容。

private void Form1_Load(object sender, EventArgs e) 
{ 
    String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true"; 

    SqlConnection con = new SqlConnection(strConnection); 
    try 
    { 
     con.Open(); 

     SqlCommand sqlCmd = new SqlCommand(); 

     sqlCmd.Connection = con; 
     sqlCmd.CommandType = CommandType.Text; 
     sqlCmd.CommandText = "Select table_name from information_schema.tables"; 

     SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd); 

     DataTable dtRecord = new DataTable(); 
     sqlDataAdap.Fill(dtRecord); 
     comboBox1.DataSource = dtRecord; 
     comboBox1.DisplayMember = "TABLE_NAME"; 
     con.Close(); 
    } 
    catch (Exception ex) 
    { 
     MessageBox.Show(ex.Message); 
    } 
} 

然后我用下面的代码填充我的DGV，但它不工作;请帮忙。

private void PopulateGridView() 
{ 
    String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true"; 
    SqlConnection con = new SqlConnection(strconnection); 

    try 
    { 
     con.Open(); 

     SqlCommand sqlCmd = new SqlCommand(); 

     sqlCmd.Connection = con; 
     sqlCmd.CommandType = CommandType.Text; 
     sqlCmd.CommandText = "select * from " + comboBox1.SelectedText; 

     SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd); 

     DataTable dtRecord = new DataTable(); 
     sqlDataAdap.Fill(dtRecord); 
     dataGridView1.AutoGenerateColumns = true; 
     dataGridView1.DataSource = dtRecord; 
     dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells); 
     con.Close(); 
    } 
    catch (Exception ex) 
    { 
     MessageBox.Show(ex.Message); 
    } 
} 

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    if (comboBox1.SelectedValue != null) 
    { 
     PopulateGridView(comboBox1.SelectedValue.ToString()); 
    } 
} 

Answer 1

只是试试这个： 更新的形式加载你的代码如下：

private void Form1_Load(object sender, EventArgs e) 
{ 
    String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true"; 
    SqlConnection con = new SqlConnection(strConnection); 
    try 
    { 
     con.Open(); 
     SqlCommand sqlCmd = new SqlCommand(); 

     sqlCmd.Connection = con; 
     sqlCmd.CommandType = CommandType.Text; 
     sqlCmd.CommandText = "Select table_name from information_schema.tables"; 

     SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd); 
     DataTable dtRecord = new DataTable(); 
     sqlDataAdap.Fill(dtRecord); 
     comboBox1.DataSource = dtRecord; 
     comboBox1.DisplayMember = "table_name"; 
     comboBox1.ValueMember = "table_name"; 
     con.Close(); 
    } 
    catch (Exception ex) 
    { 
     MessageBox.Show(ex.Message); 
    } 
} 

所以基本上你添加一个额外的行comboBox1.ValueMember = "table_name";

并使你的PopulateGridView方法如下：

private void PopulateGridView(string tblName) 
     { 
      String strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true"; 
      SqlConnection con = new SqlConnection(strConnection); 

      try 
      { 
       con.Open(); 

       SqlCommand sqlCmd = new SqlCommand(); 

       sqlCmd.Connection = con; 
       sqlCmd.CommandType = CommandType.Text; 
       sqlCmd.CommandText = "select * from " + tblName; 

       SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd); 

       DataTable dtRecord = new DataTable(); 
       sqlDataAdap.Fill(dtRecord); 
       dataGridView1.AutoGenerateColumns = true; 
       dataGridView1.DataSource = dtRecord; 
       dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells); 
       con.Close(); 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
     } 

它必须工作。 此外，我看到，您正在创建SqlConnection对象，包括SqlCommand和SqlDataAdapter。

尝试包裹起来的静态方法即

- public static SqlConnection OpenConnection() 
- public static DataTable ExecuteSelectQuery(string Query) 
- public static bool ExecuteModifyQuery(string Query) 

尝试，你可以写的代码量更少。

Answer 2

试试这个：

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) 
    { 
     if (comboBox1.SelectedValue != null) 
     { 
      string strConnection = "Data Source=HP\\SQLEXPRESS;database=MK;Integrated Security=true"; 
      SqlConnection con = new SqlConnection(strconnection); 
      try 
      { 
       con.Open(); 
       SqlCommand sqlCmd = new SqlCommand(); 

       sqlCmd.Connection = con; 
       sqlCmd.CommandType = CommandType.Text; 
       sqlCmd.CommandText = "select * from " + comboBox1.SelectedValue; 
       SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd); 

       DataTable dtRecord = new DataTable(); 
       sqlDataAdap.Fill(dtRecord); 
       dataGridView1.AutoGenerateColumns = true; 
       dataGridView1.DataSource = dtRecord; 
       dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells); 
       con.Close(); 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
     } 
    }