插入文本给objectcollection错误 [英] Inserting text gives objectcollection error
问题描述
我要插入每一行SQL到组合框,其中雇员将组合框的值,并EmployeeFirstName EmployeeLastName将组合框项目文本。然而,这行
给我这个错误:
的错误1对于System.Windows.Forms.ComboBox.ObjectCollection.Insert(INT,对象)的最佳重载方法匹配
有一些无效的
参数C:\Users\bilgisayar\Desktop\WindowsFormsApplication1 \WindowsFormsApplication1\Form1.cs 45 21 WindowsFormsApplication1 的
块引用>
解决方案定义新类
公共类EmpItem
{
公众诠释EMPID;
公共字符串empName;
}
在读取DataReader的创建这个类的一个实例,并将其添加到组合框项目集合。不要忘记设置组合框
无效comboboxrefresh()
{
comboBox1的的DisplayMember和ValueMember .DisplayMember =empName;
comboBox1.ValueMember =EMPID;
cnn.Open();
的SqlCommand CMD =新的SqlCommand(选择雇员,EmployeeFirstName,EmployeeLastName FROM员工,美国有线电视新闻网)
SqlDataReader的博士= cmd.ExecuteReader();
如果(dr.HasRows)
{
,而(dr.Read())
{
EmpItem EI =新EmpItem(){EMPID = dr.GetInt32( 0),empName = dr.GetString(1)+ dr.GetString(2)};
comboBox1.Items.Add(EI);
}
}
cnn.Close();
}
I want to insert each row in SQL into combobox, where EmployeeID will be combobox Value, and EmployeeFirstName EmployeeLastName will be text of combobox item. However this line
gives me this error:
Error 1 The best overloaded method match for 'System.Windows.Forms.ComboBox.ObjectCollection.Insert(int, object)' has some invalid arguments C:\Users\bilgisayar\Desktop\WindowsFormsApplication1\WindowsFormsApplication1\Form1.cs 45 21 WindowsFormsApplication1
解决方案Define a new class
public class EmpItem { public int empID; public string empName; }
While reading the DataReader create an instance of this class and add it to the combobox items collections. Do not forget to set the DisplayMember and ValueMember of the combobox
void comboboxrefresh() { comboBox1.DisplayMember = "empName"; comboBox1.ValueMember = "empID"; cnn.Open(); SqlCommand cmd = new SqlCommand("SELECT EmployeeID,EmployeeFirstName,EmployeeLastName FROM Employees", cnn); SqlDataReader dr = cmd.ExecuteReader(); if (dr.HasRows) { while (dr.Read()) { EmpItem ei = new EmpItem() { empID=dr.GetInt32(0), empName = dr.GetString(1) + dr.GetString(2)}; comboBox1.Items.Add(ei); } } cnn.Close(); }
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