【发布时间】：2014-05-10 07:01:55
【问题描述】：
我在使用 C# 将新条目插入 Access DB 时遇到了一点问题。我认为问题在于我的插入语句，但我包含了大部分程序，以防万一有人看到另一个严重错误。在将值输入第二种形式后，我遇到的错误发生了。我会说，也许我从第二种表格中获取值时做错了，但是查看我输入的消息框以检查，显然正在接收值。在我关闭消息框后立即抛出此错误，显示条件表达式中的数据类型不匹配。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
using System.Data.SqlClient;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace AHamblin_Larrys1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void InitializeDataGridView(string nameOfTable, string[] fieldNames)
{
//Define database connection string and dataset
String connectionString =
@"Provider=Microsoft.ACE.OLEDB.12.0;Data"
+ @" Source=C:\Users\cryow_000\Desktop\AhamblinLarrys1.accdb";
String tableName = nameOfTable;
String selectStatement = String.Format(
"select * from [{0}]", tableName);
DataSet ds = new DataSet();
OleDbConnection connection =
new OleDbConnection(connectionString);
try
{
//Open Database Connection
connection.Open();
OleDbDataAdapter da =
new OleDbDataAdapter(selectStatement, connection);
OleDbCommandBuilder cmdB =
new OleDbCommandBuilder(da);
da.MissingSchemaAction =
MissingSchemaAction.AddWithKey;
//Fill the DataSet
da.Fill(ds, tableName);
// Initialize a DataGridView.
dataGridView1.Rows.Clear();
dataGridView1.ColumnCount = ds.Tables[tableName].Columns.Count;
dataGridView1.ColumnHeadersVisible = true;
// Set the column header style.
DataGridViewCellStyle columnHeaderStyle = new DataGridViewCellStyle();
columnHeaderStyle.BackColor = Color.Beige;
columnHeaderStyle.Font = new Font("Verdana", 10, FontStyle.Bold);
dataGridView1.ColumnHeadersDefaultCellStyle = columnHeaderStyle;
// Set the column header names.
string[] fieldTitle = fieldNames;
for (int i = 0; i < dataGridView1.Columns.Count; i++)
{
dataGridView1.Columns[i].Name = fieldTitle[i];
}
// Populate the dataset rows.
string[,] table = new string[ds.Tables[tableName].Rows.Count, ds.Tables[tableName].Columns.Count];
for (int i = 0; i < ds.Tables[tableName].Rows.Count; i++)
{
for (int k = 0; k < ds.Tables[tableName].Columns.Count; k++)
{
table[i, k] = Convert.ToString(ds.Tables[tableName].Rows[i][k]);
}
}
//Populate the DataGridView with dataset rows.
var rowCount = table.GetLength(0);
var rowLength = table.GetLength(1);
for (int rowIndex = 0; rowIndex < rowCount; ++rowIndex)
{
var row = new DataGridViewRow();
for (int columnIndex = 0; columnIndex < rowLength; ++columnIndex)
{
row.Cells.Add(new DataGridViewTextBoxCell()
{
Value = table[rowIndex, columnIndex]
});
}
dataGridView1.Rows.Add(row);
}
//Close the Database Connection
connection.Close();
}
catch (OleDbException exp)
{
MessageBox.Show("Database Error:" + exp.Message.ToString());
}
finally
{
if (connection.State == ConnectionState.Open)
{
connection.Close();
}
}
}
private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
}
private void CustomerButton_Click(object sender, EventArgs e)
{
{
// Define table to use
string nameOfTable = "Customer";
// Define field names
string[] fieldNames = new string[] { "Cust. ID" , "Timestamp" , "Name" , "Street" , "City" , "State" , "ZIP" , "Telephone" , "Email" , "Balance" };
// Send data to DataGridView
InitializeDataGridView(nameOfTable, fieldNames);
insertButton.Text = "New Customer";
updateButton.Text = "Update Selected";
deleteButton.Text = "Delete Selected";
}
}
private void EmployeeButton_Click(object sender, EventArgs e)
{
string nameOfTable = "Employee";
string[] fieldNames = new string[] { "Emp. ID", "Timestamp", "Name", "Street", "City", "State", "ZIP", "Telephone", "Email", "Department" , "Manager" };
InitializeDataGridView(nameOfTable, fieldNames);
}
private void InventoryButton_Click(object sender, EventArgs e)
{
string nameOfTable = "Inventory";
string[] fieldNames = new string[] { "Item ID", "Created", "Updated", "Description", "Price", "Quantity", "Vendor" };
InitializeDataGridView(nameOfTable, fieldNames);
}
private void TransButton_Click(object sender, EventArgs e)
{
string nameOfTable = "Transaction";
string[] fieldNames = new string[] { "Trans. ID", "Timestamp", "Cust. ID", "Item ID", "Emp. ID", "Quantity", "Subtotal", "Tax", "Total" };
InitializeDataGridView(nameOfTable, fieldNames);
}
private void VendorButton_Click(object sender, EventArgs e)
{
string nameOfTable = "Vendor";
string[] fieldNames = new string[] { "Vendor ID", "Timestamp", "Name", "Street", "City", "State", "ZIP", "Telephone", "Email", "Products" };
InitializeDataGridView(nameOfTable, fieldNames);
}
private void insertButton_Click(object sender, EventArgs e)
{
if (insertButton.Text == "New Customer")
{
var Info = new CustomerInfo();
Info.Text = "New Customer";
Info.ShowDialog();
if (Info.DialogResult == DialogResult.OK)
{
string custname = Info.ReturnValue1; //values preserved after close
string dateString = Info.ReturnValue2;
string street = Info.ReturnValue3;
string city = Info.ReturnValue4;
string state = Info.ReturnValue5;
string zip = Info.ReturnValue6;
string phone = Info.ReturnValue7;
string email = Info.ReturnValue8;
string balance = Info.ReturnValue9;
MessageBox.Show(custname + " " + dateString + " " + street + " " + city + " " + state + " " + zip + " " + phone + " " + email + " " + balance);
//int cellselected = Convert.ToInt32(dataGridView1.CurrentCell.Selected);
String connectionString =
@"Provider=Microsoft.ACE.OLEDB.12.0;Data"
+ @" Source=C:\Users\cryow_000\Desktop\AhamblinLarrys1.accdb";
String tableName = "Customer";
OleDbConnection connection = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand("INSERT INTO Customer([timestamp],[cust_name],[street],[city],[zip],[state],[telephone],[email],[balance]) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)", connection);
cmd.Parameters.AddWithValue("@timestamp", OleDbType.DBTimeStamp).Value = dateString;
cmd.Parameters.AddWithValue("@cust_name", OleDbType.Char).Value = custname;
cmd.Parameters.AddWithValue("@street", OleDbType.Char).Value = street;
cmd.Parameters.AddWithValue("@city", OleDbType.Char).Value = city;
cmd.Parameters.AddWithValue("@state", OleDbType.Char).Value = state;
cmd.Parameters.AddWithValue("@zip", OleDbType.Numeric).Value = zip;
cmd.Parameters.AddWithValue("@telephone", OleDbType.Char).Value = phone;
cmd.Parameters.AddWithValue("@email", OleDbType.Char).Value = email;
cmd.Parameters.AddWithValue("@balance", OleDbType.Currency).Value = street;
cmd.Connection = connection;
connection.Open();
cmd.ExecuteNonQuery();
System.Windows.Forms.MessageBox.Show("An Item has been successfully added", "Caption", MessageBoxButtons.OKCancel, MessageBoxIcon.Information);
// Define field names
string[] fieldNames = new string[] { "Cust. ID", "Timestamp", "Name", "Street", "City", "State", "ZIP", "Telephone", "Email", "Balance" };
// Send data to DataGridView
InitializeDataGridView(tableName, fieldNames);
}
}
}
}
}
【问题讨论】：
-
除了已经提到的排序问题，您将
@balance值设置为street变量，这将导致类型不匹配。此外，这不是一个真正的问题，但使用.AddWithValue那样，您将参数的实际值设置为指定的类型，然后使用.Value将其设置为变量值。只需使用.AddWithValue("@balance", balance);
标签： c# database ms-access oledb