Question

我需要将All作为可选择的选项添加到winform上的组合框的顶部。我已经尝试了下面的两个代码，其中一个不会抛出错误但是没有添加值：

public void GetData()
{
  using (SqlConnection conn = new SqlConnection(SqlConnection))
  {
    SqlDataAdapter da = new SqlDataAdapter("select [empname] from [Testdb].[dbo].[Test] order by [empname] Asc", conn);
    conn.Open();
    da.Fill(ds, "Test");
    cboemployees.Items.Insert(0, "All");
    cboemployees.DisplayMember = "empname";
    cboemployees.DataSource = ds.Tables["Test"];
  }
}

现在这个语法会抛出错误

错误列'empname'不属于表

public void GetData()
{
 using (SqlConnection conn = new SqlConnection(SqlConnection))
 {
    SqlDataAdapter da = new SqlDataAdapter("select [empname] from [Testdb].[dbo].[Test] order by [empname] Asc", conn);
    conn.Open();
    da.Fill(ds, "Test");
    DataRow row = dt.NewRow();
    row["empname"] = "All";
    dt.Rows.InsertAt(row, -1);
    cboemployees.DataSource = dt;
 }
}

将可选项添加到绑定组合框顶部的正确方法是什么？

Answer 1

将行添加到您的表格中。

SqlDataAdapter da = new SqlDataAdapter("select [empname] from [Testdb].[dbo].[Test] order by [empname] Asc", conn);
conn.Open();

da.Fill(ds, "Test");

// Add the row for All
var allRow = ds.Tables["Test"].NewRow();
allRow[0] = "All";
ds.Tables["Test"].Rows.InsertAt(allRow, 0);

cboemployees.DisplayMember = "empname";
cboemployees.DataSource = ds.Tables["Test"];

将所有选项添加到绑定的Combobox顶部

1 个答案: